first commit

core/modules/views_ui/tests/modules/views_ui_test/css/views_ui_test.test.css

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+/**
+ * @file
+ * Just a placeholder file for the test.
+ */

core/modules/views_ui/tests/modules/views_ui_test/views_ui_test.info.yml

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+name: 'Views UI Test'
+type: module
+description: 'Test module for Views UI.'
+package: Testing
+# version: VERSION
+dependencies:
+  - drupal:views_ui
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/views_ui/tests/modules/views_ui_test/views_ui_test.libraries.yml

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+views_ui_test.test:
+  css:
+    component:
+      css/views_ui_test.test.css: {}

core/modules/views_ui/tests/modules/views_ui_test/views_ui_test.module

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+<?php
+
+/**
+ * @file
+ * Helper module for Views UI tests.
+ */
+
+/**
+ * Implements hook_views_preview_info_alter().
+ *
+ * Add a row count row to the live preview area.
+ */
+function views_ui_test_views_preview_info_alter(&$rows, $view) {
+  $data = ['#markup' => t('Test row count')];
+  $data['#attached']['library'][] = 'views_ui_test/views_ui_test.test';
+  $rows['query'][] = [['data' => $data], count($view->result)];
+}

core/modules/views_ui/tests/modules/views_ui_test_field/views_ui_test_field.info.yml

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+name: 'Views test field'
+type: module
+description: 'Add custom global field for testing purposes.'
+package: Testing
+# version: VERSION
+dependencies:
+  - drupal:views_ui
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/views_ui/tests/modules/views_ui_test_field/views_ui_test_field.module

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+<?php
+
+/**
+ * @file
+ * ViewsUI Test field module.
+ */
+
+use Drupal\Core\Form\FormStateInterface;
+
+/**
+ * Implements hook_form_FORM_ID_alter() for views_ui_add_handler_form.
+ *
+ * Changes the label for one of the tests fields to validate this label is not
+ * searched on.
+ */
+function views_ui_test_field_form_views_ui_add_handler_form_alter(&$form, FormStateInterface $form_state) {
+  $form['options']['name']['#options']['views.views_test_field_1']['title']['data']['#title'] .= ' FIELD_1_LABEL';
+}

core/modules/views_ui/tests/modules/views_ui_test_field/views_ui_test_field.views.inc

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+<?php
+
+/**
+ * @file
+ * Provide views data for testing purposes.
+ */
+
+/**
+ * Implements hook_views_data().
+ */
+function views_ui_test_field_views_data() {
+
+  $data['views']['views_test_field_1'] = [
+    'title' => t('Views test field 1 - FIELD_1_TITLE'),
+    'help' => t('Field 1 for testing purposes - FIELD_1_DESCRIPTION'),
+    'field' => [
+      'id' => 'views_test_field_1',
+    ],
+  ];
+  $data['views']['views_test_field_2'] = [
+    'title' => t('Views test field 2 - FIELD_2_TITLE'),
+    'help' => t('Field 2 for testing purposes - FIELD_2_DESCRIPTION'),
+    'field' => [
+      'id' => 'views_test_field_2',
+    ],
+  ];
+
+  return $data;
+}

core/modules/views_ui/tests/src/Functional/AnalyzeTest.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the views analyze system.
+ *
+ * @group views_ui
+ */
+class AnalyzeTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * Tests that analyze works in general.
+   */
+  public function testAnalyzeBasic(): void {
+    $this->drupalLogin($this->adminUser);
+
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    $this->assertSession()->linkExists('Analyze view');
+
+    // This redirects the user to the analyze form.
+    $this->clickLink('Analyze view');
+    $this->assertSession()->titleEquals('View analysis | Drupal');
+
+    foreach (['ok', 'warning', 'error'] as $type) {
+      // Check that analyze messages with the expected type found.
+      $this->assertSession()->elementExists('css', 'div.' . $type);
+    }
+
+    // This redirects the user back to the main views edit page.
+    $this->submitForm([], 'Ok');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/AreaEntityUITest.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\block\Entity\Block;
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\views\Entity\View;
+
+/**
+ * Tests the entity area UI test.
+ *
+ * @see \Drupal\views\Plugin\views\area\Entity
+ * @group views_ui
+ */
+class AreaEntityUITest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['entity_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  public function testUI(): void {
+    // Set up a block and an entity_test entity.
+    $block = Block::create(['id' => 'test_id', 'plugin' => 'system_main_block', 'theme' => 'stark']);
+    $block->save();
+
+    $entity_test = EntityTest::create(['bundle' => 'entity_test']);
+    $entity_test->save();
+
+    $default = $this->randomView([]);
+    $id = $default['id'];
+    $view = View::load($id);
+
+    $this->drupalGet($view->toUrl('edit-form'));
+
+    // Add a global NULL argument to the view for testing argument placeholders.
+    $this->drupalGet("admin/structure/views/nojs/add-handler/{$id}/page_1/argument");
+    $this->submitForm(['name[views.null]' => TRUE], 'Add and configure contextual filters');
+    $this->submitForm([], 'Apply');
+
+    // Configure both the entity_test area header and the block header to
+    // reference the given entities.
+    $this->drupalGet("admin/structure/views/nojs/add-handler/{$id}/page_1/header");
+    $this->submitForm(['name[views.entity_block]' => TRUE], 'Add and configure header');
+    $this->submitForm(['options[target]' => $block->id()], 'Apply');
+
+    $this->drupalGet("admin/structure/views/nojs/add-handler/{$id}/page_1/header");
+    $this->submitForm(['name[views.entity_entity_test]' => TRUE], 'Add and configure header');
+    $this->submitForm(['options[target]' => $entity_test->id()], 'Apply');
+
+    $this->submitForm([], 'Save');
+
+    // Confirm the correct target identifiers were saved for both entities.
+    $view = View::load($id);
+    $header = $view->getDisplay('default')['display_options']['header'];
+    $this->assertEquals(['entity_block', 'entity_entity_test'], array_keys($header));
+
+    $this->assertEquals($block->id(), $header['entity_block']['target']);
+    $this->assertEquals($entity_test->uuid(), $header['entity_entity_test']['target']);
+
+    // Confirm that the correct serial ID (for the entity_test) and config ID
+    // (for the block) are displayed in the form.
+    $this->drupalGet("admin/structure/views/nojs/handler/$id/page_1/header/entity_block");
+    $this->assertSession()->fieldValueEquals('options[target]', $block->id());
+
+    $this->drupalGet("admin/structure/views/nojs/handler/$id/page_1/header/entity_entity_test");
+    $this->assertSession()->fieldValueEquals('options[target]', $entity_test->id());
+
+    // Replace the header target entities with argument placeholders.
+    $this->drupalGet("admin/structure/views/nojs/handler/{$id}/page_1/header/entity_block");
+    $this->submitForm(['options[target]' => '{{ raw_arguments.null }}'], 'Apply');
+    $this->drupalGet("admin/structure/views/nojs/handler/{$id}/page_1/header/entity_entity_test");
+    $this->submitForm(['options[target]' => '{{ raw_arguments.null }}'], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Confirm that the argument placeholders are saved.
+    $view = View::load($id);
+    $header = $view->getDisplay('default')['display_options']['header'];
+    $this->assertEquals(['entity_block', 'entity_entity_test'], array_keys($header));
+
+    $this->assertEquals('{{ raw_arguments.null }}', $header['entity_block']['target']);
+    $this->assertEquals('{{ raw_arguments.null }}', $header['entity_entity_test']['target']);
+
+    // Confirm that the argument placeholders are still displayed in the form.
+    $this->drupalGet("admin/structure/views/nojs/handler/$id/page_1/header/entity_block");
+    $this->assertSession()->fieldValueEquals('options[target]', '{{ raw_arguments.null }}');
+
+    $this->drupalGet("admin/structure/views/nojs/handler/$id/page_1/header/entity_entity_test");
+    $this->assertSession()->fieldValueEquals('options[target]', '{{ raw_arguments.null }}');
+
+    // Change the targets for both headers back to the entities.
+    $this->drupalGet("admin/structure/views/nojs/handler/{$id}/page_1/header/entity_block");
+    $this->submitForm(['options[target]' => $block->id()], 'Apply');
+    $this->drupalGet("admin/structure/views/nojs/handler/{$id}/page_1/header/entity_entity_test");
+    $this->submitForm(['options[target]' => $entity_test->id()], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Confirm the targets were again saved correctly and not skipped based on
+    // the previous form value.
+    $view = View::load($id);
+    $header = $view->getDisplay('default')['display_options']['header'];
+    $this->assertEquals(['entity_block', 'entity_entity_test'], array_keys($header));
+
+    $this->assertEquals($block->id(), $header['entity_block']['target']);
+    $this->assertEquals($entity_test->uuid(), $header['entity_entity_test']['target']);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ArgumentValidatorTest.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the Argument validator through the UI.
+ *
+ * @group views_ui
+ */
+class ArgumentValidatorTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_argument'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the 'Specify validation criteria' checkbox functionality.
+   */
+  public function testSpecifyValidation(): void {
+    // Specify a validation based on Node for the 'id' argument on the default
+    // display and assert that this works.
+    $this->saveArgumentHandlerWithValidationOptions(TRUE);
+    $view = Views::getView('test_argument');
+    $handler = $view->getHandler('default', 'argument', 'id');
+    $this->assertTrue($handler['specify_validation'], 'Validation for this argument has been turned on.');
+    $this->assertEquals('entity:node', $handler['validate']['type'], 'Validation for the argument is based on the node.');
+
+    // Uncheck the 'Specify validation criteria' checkbox and expect the
+    // validation type to be reset back to 'none'.
+    $this->saveArgumentHandlerWithValidationOptions(FALSE);
+    $view = Views::getView('test_argument');
+    $handler = $view->getHandler('default', 'argument', 'id');
+    $this->assertFalse($handler['specify_validation'], 'Validation for this argument has been turned off.');
+    $this->assertEquals('none', $handler['validate']['type'], 'Validation for the argument has been reverted to Basic Validation.');
+  }
+
+  /**
+   * Saves the test_argument view with changes made to the argument handler.
+   *
+   * @param bool $specify_validation
+   *   The form validation.
+   */
+  protected function saveArgumentHandlerWithValidationOptions($specify_validation) {
+    $options = [
+      'options[validate][type]' => 'entity---node',
+      'options[specify_validation]' => $specify_validation,
+    ];
+    $this->drupalGet('admin/structure/views/nojs/handler/test_argument/default/argument/id');
+    $this->submitForm($options, 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_argument');
+    $this->submitForm([], 'Save');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/CachedDataUITest.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the shared tempstore cache in the UI.
+ *
+ * @group views_ui
+ */
+class CachedDataUITest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the shared tempstore views data in the UI.
+   */
+  public function testCacheData(): void {
+    $views_admin_user_uid = $this->fullAdminUser->id();
+
+    $temp_store = $this->container->get('tempstore.shared')->get('views');
+    // The view should not be locked.
+    $this->assertNull($temp_store->getMetadata('test_view'), 'The view is not locked.');
+
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    // Make sure we have 'changes' to the view.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/default/title');
+    $this->submitForm([], 'Apply');
+    $this->assertSession()->pageTextContains('You have unsaved changes.');
+    $this->assertEquals($views_admin_user_uid, $temp_store->getMetadata('test_view')->getOwnerId(), 'View cache has been saved.');
+
+    $view_cache = $temp_store->get('test_view');
+    // The view should be enabled.
+    $this->assertTrue($view_cache->status(), 'The view is enabled.');
+    // The view should now be locked.
+    $this->assertEquals($views_admin_user_uid, $temp_store->getMetadata('test_view')->getOwnerId(), 'The view is locked.');
+
+    // Cancel the view edit and make sure the cache is deleted.
+    $this->submitForm([], 'Cancel');
+    $this->assertNull($temp_store->getMetadata('test_view'), 'Shared tempstore data has been removed.');
+    // Test we are redirected to the view listing page.
+    $this->assertSession()->addressEquals('admin/structure/views');
+
+    // Log in with another user and make sure the view is locked and break.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/default/title');
+    $this->submitForm([], 'Apply');
+    $this->drupalLogin($this->adminUser);
+
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    // Test that save and cancel buttons are not shown.
+    $this->assertSession()->buttonNotExists('Save');
+    $this->assertSession()->buttonNotExists('Cancel');
+    // Test we have the break lock link.
+    $this->assertSession()->linkByHrefExists('admin/structure/views/view/test_view/break-lock');
+    // Break the lock.
+    $this->clickLink('break this lock');
+    $this->submitForm([], 'Break lock');
+    // Test that save and cancel buttons are shown.
+    $this->assertSession()->buttonExists('Save');
+    $this->assertSession()->buttonExists('Cancel');
+    // Test we can save the view.
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains("The view Test view has been saved.");
+
+    // Test that a deleted view has no tempstore data.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/default/title');
+    $this->submitForm([], 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view/delete');
+    $this->submitForm([], 'Delete');
+    // No view tempstore data should be returned for this view after deletion.
+    $this->assertNull($temp_store->getMetadata('test_view'), 'View tempstore data has been removed after deletion.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/CustomBooleanTest.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the UI and functionality for the Custom boolean field handler options.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\field\Boolean
+ */
+class CustomBooleanTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * \Drupal\views\Tests\ViewTestBase::viewsData().
+   */
+  public function viewsData() {
+    $data = parent::viewsData();
+    $data['views_test_data']['age']['field']['id'] = 'boolean';
+    return $data;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function dataSet() {
+    $data = parent::dataSet();
+    $data[0]['age'] = 0;
+    $data[3]['age'] = 0;
+    return $data;
+  }
+
+  /**
+   * Tests the setting and output of custom labels for boolean values.
+   */
+  public function testCustomOption(): void {
+    // Add the boolean field handler to the test view.
+    $view = Views::getView('test_view');
+    $view->setDisplay();
+
+    $view->displayHandlers->get('default')->overrideOption('fields', [
+      'age' => [
+        'id' => 'age',
+        'table' => 'views_test_data',
+        'field' => 'age',
+        'relationship' => 'none',
+        'plugin_id' => 'boolean',
+      ],
+    ]);
+    $view->save();
+
+    $this->executeView($view);
+
+    $custom_true = 'Yay';
+    $custom_false = 'Nay';
+
+    // Set up some custom value mappings for different types.
+    $custom_values = [
+      'plain' => [
+        'true' => $custom_true,
+        'false' => $custom_false,
+        'test' => 'assertStringContainsString',
+      ],
+      'allowed tag' => [
+        'true' => '<p>' . $custom_true . '</p>',
+        'false' => '<p>' . $custom_false . '</p>',
+        'test' => 'assertStringContainsString',
+      ],
+      'disallowed tag' => [
+        'true' => '<script>' . $custom_true . '</script>',
+        'false' => '<script>' . $custom_false . '</script>',
+        'test' => 'assertStringNotContainsString',
+      ],
+    ];
+
+    // Run the same tests on each type.
+    foreach ($custom_values as $type => $values) {
+      $options = [
+        'options[type]' => 'custom',
+        'options[type_custom_true]' => $values['true'],
+        'options[type_custom_false]' => $values['false'],
+      ];
+      $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/field/age');
+      $this->submitForm($options, 'Apply');
+
+      // Save the view.
+      $this->drupalGet('admin/structure/views/view/test_view');
+      $this->submitForm([], 'Save');
+
+      $view = Views::getView('test_view');
+      $output = $view->preview();
+      $output = \Drupal::service('renderer')->renderRoot($output);
+      $this->{$values['test']}($values['true'], (string) $output, "Expected custom boolean TRUE value {$values['true']} in output for $type");
+      $this->{$values['test']}($values['false'], (string) $output, "Expected custom boolean FALSE value {$values['false']} in output for $type");
+    }
+  }
+
+  /**
+   * Tests the setting and output of custom labels for boolean values.
+   */
+  public function testCustomOptionTemplate(): void {
+    // Install theme to test with template system.
+    \Drupal::service('theme_installer')->install(['views_test_theme']);
+
+    // Set the default theme for Views preview.
+    $this->config('system.theme')
+      ->set('default', 'views_test_theme')
+      ->save();
+    $this->assertEquals('views_test_theme', $this->config('system.theme')->get('default'));
+
+    // Add the boolean field handler to the test view.
+    $view = Views::getView('test_view');
+    $view->setDisplay();
+
+    $view->displayHandlers->get('default')->overrideOption('fields', [
+      'age' => [
+        'id' => 'age',
+        'table' => 'views_test_data',
+        'field' => 'age',
+        'relationship' => 'none',
+        'plugin_id' => 'boolean',
+      ],
+    ]);
+    $view->save();
+
+    $this->executeView($view);
+
+    $custom_true = 'Yay';
+    $custom_false = 'Nay';
+
+    // Set up some custom value mappings for different types.
+    $custom_values = [
+      'plain' => [
+        'true' => $custom_true,
+        'false' => $custom_false,
+        'test' => 'assertStringContainsString',
+      ],
+      'allowed tag' => [
+        'true' => '<p>' . $custom_true . '</p>',
+        'false' => '<p>' . $custom_false . '</p>',
+        'test' => 'assertStringContainsString',
+      ],
+      'disallowed tag' => [
+        'true' => '<script>' . $custom_true . '</script>',
+        'false' => '<script>' . $custom_false . '</script>',
+        'test' => 'assertStringNotContainsString',
+      ],
+    ];
+
+    // Run the same tests on each type.
+    foreach ($custom_values as $type => $values) {
+      $options = [
+        'options[type]' => 'custom',
+        'options[type_custom_true]' => $values['true'],
+        'options[type_custom_false]' => $values['false'],
+      ];
+      $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/field/age');
+      $this->submitForm($options, 'Apply');
+
+      // Save the view.
+      $this->drupalGet('admin/structure/views/view/test_view');
+      $this->submitForm([], 'Save');
+
+      $view = Views::getView('test_view');
+      $output = $view->preview();
+      $output = \Drupal::service('renderer')->renderRoot($output);
+      $this->{$values['test']}($values['true'], (string) $output, "Expected custom boolean TRUE value {$values['true']} in output for $type");
+      $this->{$values['test']}($values['false'], (string) $output, "Expected custom boolean FALSE value {$values['false']} in output for $type");
+
+      // Assert that we are using the correct template.
+      $this->assertStringContainsString('llama', (string) $output);
+    }
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DefaultViewsTest.php

@@ -0,0 +1,226 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Core\Url;
+use Drupal\user\Entity\Role;
+use Drupal\user\RoleInterface;
+
+/**
+ * Tests enabling, disabling, and reverting default views via the listing page.
+ *
+ * @group views_ui
+ */
+class DefaultViewsTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view_status', 'test_page_display_menu', 'test_page_display_arguments'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->placeBlock('page_title_block');
+  }
+
+  /**
+   * Tests default views.
+   */
+  public function testDefaultViews(): void {
+    // Make sure the view starts off as disabled (does not appear on the listing
+    // page).
+    $edit_href = 'admin/structure/views/view/glossary';
+    $this->drupalGet('admin/structure/views');
+    // @todo Disabled default views do now appear on the front page. Test this
+    // behavior with templates instead.
+    // $this->assertSession()->linkByHrefNotExists($edit_href);
+
+    // Enable the view, and make sure it is now visible on the main listing
+    // page.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Enable', '/glossary/');
+    $this->assertSession()->addressEquals('admin/structure/views');
+    $this->assertSession()->linkByHrefExists($edit_href);
+
+    // It should not be possible to revert the view yet.
+    // @todo Figure out how to handle this with the new configuration system.
+    // $this->assertSession()->linkNotExists('Revert');
+    // $revert_href = 'admin/structure/views/view/glossary/revert';
+    // $this->assertSession()->linkByHrefNotExists($revert_href);
+
+    // Edit the view and change the title. Make sure that the new title is
+    // displayed.
+    $new_title = $this->randomMachineName(16);
+    $edit = ['title' => $new_title];
+    $this->drupalGet('admin/structure/views/nojs/display/glossary/page_1/title');
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet('admin/structure/views/view/glossary/edit/page_1');
+    $this->submitForm([], 'Save');
+    $this->drupalGet('glossary');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($new_title);
+
+    // Save another view in the UI.
+    $this->drupalGet('admin/structure/views/nojs/display/archive/page_1/title');
+    $this->submitForm([], 'Apply');
+    $this->drupalGet('admin/structure/views/view/archive/edit/page_1');
+    $this->submitForm([], 'Save');
+
+    // Check there is an enable link. i.e. The view has not been enabled after
+    // editing.
+    $this->drupalGet('admin/structure/views');
+    $this->assertSession()->linkByHrefExists('admin/structure/views/view/archive/enable');
+    // Enable it again so it can be tested for access permissions.
+    $this->clickViewsOperationLink('Enable', '/archive/');
+
+    // It should now be possible to revert the view. Do that, and make sure the
+    // view title we added above no longer is displayed.
+    // $this->drupalGet('admin/structure/views');
+    // $this->assertSession()->linkExists('Revert');
+    // $this->assertSession()->linkByHrefExists($revert_href);
+    // $this->drupalGet($revert_href);
+    // $this->submitForm(array(), 'Revert');
+    // $this->drupalGet('glossary');
+    // $this->assertSession()->pageTextNotContains($new_title);
+
+    // Duplicate the view and check that the normal schema of duplicated views is used.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Duplicate', '/glossary');
+    $edit = [
+      'id' => 'duplicate_of_glossary',
+    ];
+    $this->assertSession()->titleEquals('Duplicate of Glossary | Drupal');
+    $this->submitForm($edit, 'Duplicate');
+    $this->assertSession()->addressEquals('admin/structure/views/view/duplicate_of_glossary');
+
+    // Duplicate a view and set a custom name.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Duplicate', '/glossary');
+    $random_name = $this->randomMachineName();
+    $this->submitForm(['id' => $random_name], 'Duplicate');
+    $this->assertSession()->addressEquals("admin/structure/views/view/$random_name");
+
+    // Now disable the view, and make sure it stops appearing on the main view
+    // listing page but instead goes back to displaying on the disabled views
+    // listing page.
+    // @todo Test this behavior with templates instead.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Disable', '/glossary/');
+    // $this->assertSession()->addressEquals('admin/structure/views');
+    // $this->assertSession()->linkByHrefNotExists($edit_href);
+    // The easiest way to verify it appears on the disabled views listing page
+    // is to try to click the "enable" link from there again.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Enable', '/glossary/');
+    $this->assertSession()->addressEquals('admin/structure/views');
+    $this->assertSession()->linkByHrefExists($edit_href);
+
+    // Clear permissions for anonymous users to check access for default views.
+    Role::load(RoleInterface::ANONYMOUS_ID)->revokePermission('access content')->save();
+
+    // Test the default views disclose no data by default.
+    $this->drupalLogout();
+    $this->drupalGet('glossary');
+    $this->assertSession()->statusCodeEquals(403);
+    $this->drupalGet('archive');
+    $this->assertSession()->statusCodeEquals(403);
+
+    // Test deleting a view.
+    $this->drupalLogin($this->fullAdminUser);
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Delete', '/glossary/');
+    // Submit the confirmation form.
+    $this->submitForm([], 'Delete');
+    // Ensure the view is no longer listed.
+    $this->assertSession()->addressEquals('admin/structure/views');
+    $this->assertSession()->linkByHrefNotExists($edit_href);
+    // Ensure the view is no longer available.
+    $this->drupalGet($edit_href);
+    $this->assertSession()->statusCodeEquals(404);
+    $this->assertSession()->pageTextContains('Page not found');
+
+    // Delete all duplicated Glossary views.
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Delete', 'duplicate_of_glossary');
+    // Submit the confirmation form.
+    $this->submitForm([], 'Delete');
+
+    $this->drupalGet('glossary');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->drupalGet('admin/structure/views');
+    $this->clickViewsOperationLink('Delete', $random_name);
+    // Submit the confirmation form.
+    $this->submitForm([], 'Delete');
+    $this->drupalGet('glossary');
+    $this->assertSession()->statusCodeEquals(404);
+    $this->assertSession()->pageTextContains('Page not found');
+  }
+
+  /**
+   * Tests that enabling views moves them to the correct table.
+   */
+  public function testSplitListing(): void {
+    $this->drupalGet('admin/structure/views');
+    $this->assertSession()->elementNotExists('xpath', '//div[@id="views-entity-list"]/div[@class = "views-list-section enabled"]/table//td/text()[contains(., "test_view_status")]');
+    $this->assertSession()->elementsCount('xpath', '//div[@id="views-entity-list"]/div[@class = "views-list-section disabled"]/table//td/text()[contains(., "test_view_status")]', 1);
+
+    // Enable the view.
+    $this->clickViewsOperationLink('Enable', '/test_view_status/');
+    $this->assertSession()->elementNotExists('xpath', '//div[@id="views-entity-list"]/div[@class = "views-list-section disabled"]/table//td/text()[contains(., "test_view_status")]');
+    $this->assertSession()->elementsCount('xpath', '//div[@id="views-entity-list"]/div[@class = "views-list-section enabled"]/table//td/text()[contains(., "test_view_status")]', 1);
+
+    // Attempt to disable the view by path directly, with no token.
+    $this->drupalGet('admin/structure/views/view/test_view_status/disable');
+    $this->assertSession()->statusCodeEquals(403);
+  }
+
+  /**
+   * Tests that page displays show the correct path.
+   */
+  public function testPathDestination(): void {
+    $this->drupalGet('admin/structure/views');
+
+    // Check that links to views on default tabs are rendered correctly.
+    $this->assertSession()->linkByHrefExists('test_page_display_menu');
+    $this->assertSession()->linkByHrefNotExists('test_page_display_menu/default');
+    $this->assertSession()->linkByHrefExists('test_page_display_menu/local');
+
+    // Check that a dynamic path is shown as text.
+    $this->assertSession()->responseContains('test_route_with_suffix/%/suffix');
+    $this->assertSession()->linkByHrefNotExists(Url::fromUri('base:test_route_with_suffix/%/suffix')->toString());
+  }
+
+  /**
+   * Click a link to perform an operation on a view.
+   *
+   * In general, we expect lots of links titled "enable" or "disable" on the
+   * various views listing pages, and they might have tokens in them. So we
+   * need special code to find the correct one to click.
+   *
+   * @param $label
+   *   Text between the anchor tags of the desired link.
+   * @param $unique_href_part
+   *   A unique string that is expected to occur within the href of the desired
+   *   link. For example, if the link URL is expected to look like
+   *   "admin/structure/views/view/glossary/*", then "/glossary/" could be
+   *   passed as the expected unique string.
+   */
+  public function clickViewsOperationLink($label, $unique_href_part) {
+    $this->assertSession()->elementExists('xpath', "//a[normalize-space(text())='$label' and contains(@href, '$unique_href_part')]")->click();
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayAttachmentTest.php

@@ -0,0 +1,139 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the UI for the attachment display plugin.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\display\Attachment
+ */
+class DisplayAttachmentTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   * .
+   */
+  public static $testViews = ['test_attachment_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the attachment UI.
+   */
+  public function testAttachmentUI(): void {
+    $this->drupalGet('admin/structure/views/view/test_attachment_ui/edit/attachment_1');
+    $this->assertSession()->pageTextContains('Not defined');
+
+    $attachment_display_url = 'admin/structure/views/nojs/display/test_attachment_ui/attachment_1/displays';
+    $this->drupalGet($attachment_display_url);
+    // Display labels should be escaped.
+    $this->assertSession()->assertEscaped('<em>Page</em>');
+
+    $this->assertSession()->checkboxNotChecked("edit-displays-default");
+    $this->assertSession()->checkboxNotChecked("edit-displays-page-1");
+
+    // Save the attachments and test the value on the view.
+    $this->drupalGet($attachment_display_url);
+    $this->submitForm(['displays[page_1]' => 1], 'Apply');
+    // Options summary should be escaped.
+    $this->assertSession()->assertEscaped('<em>Page</em>');
+    $this->assertSession()->responseNotContains('<em>Page</em>');
+    $this->assertSession()->elementAttributeContains('xpath', '//a[@id = "views-attachment-1-displays"]', 'title', 'Page');
+    $this->submitForm([], 'Save');
+
+    $view = Views::getView('test_attachment_ui');
+    $view->initDisplay();
+    $this->assertEquals(['page_1'], array_keys(array_filter($view->displayHandlers->get('attachment_1')->getOption('displays'))), 'The attached displays got saved as expected');
+
+    $this->drupalGet($attachment_display_url);
+    $this->submitForm([
+      'displays[default]' => 1,
+      'displays[page_1]' => 1,
+    ], 'Apply');
+    $this->assertSession()->elementAttributeContains('xpath', '//a[@id = "views-attachment-1-displays"]', 'title', 'Multiple displays');
+    $this->submitForm([], 'Save');
+
+    $view = Views::getView('test_attachment_ui');
+    $view->initDisplay();
+    $this->assertEquals(['default', 'page_1'], array_keys($view->displayHandlers->get('attachment_1')->getOption('displays')), 'The attached displays got saved as expected');
+  }
+
+  /**
+   * Tests the attachment working after the attached page was deleted.
+   */
+  public function testRemoveAttachedDisplay(): void {
+    // Create a view.
+    $view = $this->randomView();
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+    $attachment_display_url = 'admin/structure/views/nojs/display/' . $view['id'] . '/attachment_1/displays';
+
+    // Open the Page display and create the attachment display.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Add Attachment');
+    $this->assertSession()->pageTextContains('Not defined');
+
+    // Attach the Attachment to the Page display.
+    $this->drupalGet($attachment_display_url);
+    $this->submitForm(['displays[page_1]' => 1], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Open the Page display and mark it as deleted.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-delete');
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Delete Page');
+
+    // Open the attachment display and save it.
+    $this->drupalGet($path_prefix . '/attachment_1');
+    $this->submitForm([], 'Save');
+
+    // Check that there is no warning for the removed page display.
+    $this->assertSession()->pageTextNotContains("Plugin ID 'page_1' was not found.");
+
+    // Check that the attachment is no longer linked to the removed display.
+    $this->assertSession()->pageTextContains('Not defined');
+
+  }
+
+  /**
+   * Tests the attachment after changing machine name.
+   */
+  public function testAttachmentOnAttachedMachineNameChange(): void {
+
+    $view = $this->randomView();
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+    $attachment_display_url = 'admin/structure/views/nojs/display/' . $view['id'] . '/attachment_1/displays';
+
+    // Open the Page display and create the attachment display.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Add Attachment');
+    $this->assertSession()->pageTextContains('Not defined');
+
+    // Attach the Attachment to the Default and   Page display.
+    $this->drupalGet($attachment_display_url);
+    $this->submitForm(['displays[default]' => 1, 'displays[page_1]' => 1], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Change the machine name of the page.
+    $this->drupalGet('admin/structure/views/nojs/display/' . $view['id'] . '/page_1/display_id');
+    $this->submitForm(['display_id' => 'page_new_id'], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Check that the attachment is still attached to the page.
+    $this->drupalGet($attachment_display_url);
+    $this->assertSession()->checkboxChecked("edit-displays-default");
+    $this->assertSession()->checkboxChecked("edit-displays-page-new-id");
+
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayCRUDTest.php

@@ -0,0 +1,174 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests creation, retrieval, updating, and deletion of displays in the Web UI.
+ *
+ * @group views_ui
+ */
+class DisplayCRUDTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_display'];
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['contextual'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests adding a display.
+   */
+  public function testAddDisplay(): void {
+    // Show the default display.
+    $this->config('views.settings')->set('ui.show.default_display', TRUE)->save();
+
+    $settings['page[create]'] = FALSE;
+    $view = $this->randomView($settings);
+
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+    $this->drupalGet($path_prefix);
+
+    // Add a new display.
+    $this->submitForm([], 'Add Page');
+    $this->assertSession()->linkByHrefExists($path_prefix . '/page_1', 0, 'Make sure after adding a display the new display appears in the UI');
+
+    $this->assertSession()->linkNotExists('Default*', 'Make sure the default display is not marked as changed.');
+    $this->assertSession()->linkExists('Page*', 0, 'Make sure the added display is marked as changed.');
+
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_1/path");
+    $this->submitForm(['path' => 'test/path'], 'Apply');
+    $this->submitForm([], 'Save');
+  }
+
+  /**
+   * Tests removing a display.
+   */
+  public function testRemoveDisplay(): void {
+    $view = $this->randomView();
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+
+    // Make sure there is no delete button on the default display.
+    $this->drupalGet($path_prefix . '/default');
+    $this->assertSession()->buttonNotExists('edit-displays-settings-settings-content-tab-content-details-top-actions-delete');
+
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-delete');
+
+    // Delete the page, so we can test the undo process.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Delete Page');
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-undo-delete');
+    // Test that the display link is marked as to be deleted.
+    $this->assertSession()->elementExists('xpath', "//a[contains(@href, '{$path_prefix}/page_1') and contains(@class, 'views-display-deleted-link')]");
+
+    // Undo the deleting of the display.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Undo delete of Page');
+    $this->assertSession()->buttonNotExists('edit-displays-settings-settings-content-tab-content-details-top-actions-undo-delete');
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-delete');
+
+    // Now delete again and save the view.
+    $this->drupalGet($path_prefix . '/page_1');
+    $this->submitForm([], 'Delete Page');
+    $this->submitForm([], 'Save');
+
+    $this->assertSession()->linkByHrefNotExists($path_prefix . '/page_1', 'Make sure there is no display tab for the deleted display.');
+
+    // Test deleting a display that has a modified machine name.
+    $view = $this->randomView();
+    $machine_name = 'new_machine_name';
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_1/display_id");
+    $this->submitForm(['display_id' => $machine_name], 'Apply');
+    $this->submitForm([], 'Delete Page');
+    $this->submitForm([], 'Save');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->linkByHrefNotExists($path_prefix . '/new_machine_name', 'Make sure there is no display tab for the deleted display.');
+  }
+
+  /**
+   * Tests that the correct display is loaded by default.
+   */
+  public function testDefaultDisplay(): void {
+    $this->drupalGet('admin/structure/views/view/test_display');
+    $this->assertSession()->elementsCount('xpath', '//*[@id="views-page-1-display-title"]', 1);
+  }
+
+  /**
+   * Tests the duplicating of a display.
+   */
+  public function testDuplicateDisplay(): void {
+    $view = $this->randomView();
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+    $path = $view['page[path]'];
+
+    $this->drupalGet($path_prefix);
+    $this->submitForm([], 'Duplicate Page');
+    // Verify that the user got redirected to the new display.
+    $this->assertSession()->linkByHrefExists($path_prefix . '/page_2', 0, 'Make sure after duplicating the new display appears in the UI');
+    $this->assertSession()->addressEquals($path_prefix . '/page_2');
+
+    // Set the title and override the css classes.
+    $random_title = $this->randomMachineName();
+    $random_css = $this->randomMachineName();
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_2/title");
+    $this->submitForm(['title' => $random_title], 'Apply');
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_2/css_class");
+    $this->submitForm([
+      'override[dropdown]' => 'page_2',
+      'css_class' => $random_css,
+    ], 'Apply');
+
+    // Duplicate as a different display type.
+    $this->submitForm([], 'Duplicate as Block');
+    $this->assertSession()->linkByHrefExists($path_prefix . '/block_1', 0, 'Make sure after duplicating the new display appears in the UI');
+    $this->assertSession()->addressEquals($path_prefix . '/block_1');
+    $this->assertSession()->pageTextContains('Block settings');
+    $this->assertSession()->pageTextNotContains('Page settings');
+
+    $this->submitForm([], 'Save');
+    $view = Views::getView($view['id']);
+    $view->initDisplay();
+
+    $page_2 = $view->displayHandlers->get('page_2');
+    $this->assertNotEmpty($page_2, 'The new page display got saved.');
+    $this->assertEquals('Page', $page_2->display['display_title']);
+    $this->assertEquals($path, $page_2->display['display_options']['path']);
+    $block_1 = $view->displayHandlers->get('block_1');
+    $this->assertNotEmpty($block_1, 'The new block display got saved.');
+    $this->assertEquals('block', $block_1->display['display_plugin']);
+    $this->assertEquals('Block', $block_1->display['display_title'], 'The new display title got generated as expected.');
+    $this->assertFalse(isset($block_1->display['display_options']['path']));
+    $this->assertEquals($random_title, $block_1->getOption('title'), 'The overridden title option from the display got copied into the duplicate');
+    $this->assertEquals($random_css, $block_1->getOption('css_class'), 'The overridden css_class option from the display got copied into the duplicate');
+
+    // Test duplicating a display after changing the machine name.
+    $view_id = $view->id();
+    $this->drupalGet("admin/structure/views/nojs/display/{$view_id}/page_2/display_id");
+    $this->submitForm(['display_id' => 'page_new'], 'Apply');
+    $this->submitForm([], 'Duplicate as Block');
+    $this->submitForm([], 'Save');
+    $view = Views::getView($view_id);
+    $view->initDisplay();
+    $this->assertNotNull($view->displayHandlers->get('page_new'), 'The original display is saved with a changed id');
+    $this->assertNotNull($view->displayHandlers->get('block_2'), 'The duplicate display is saved with new id');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayExtenderUITest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the display extender UI.
+ *
+ * @group views_ui
+ */
+class DisplayExtenderUITest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the display extender UI.
+   */
+  public function testDisplayExtenderUI(): void {
+    $this->config('views.settings')->set('display_extenders', ['display_extender_test'])->save();
+
+    $view = Views::getView('test_view');
+    $view_edit_url = "admin/structure/views/view/{$view->storage->id()}/edit";
+    $display_option_url = 'admin/structure/views/nojs/display/test_view/default/test_extender_test_option';
+
+    $this->drupalGet($view_edit_url);
+    $this->assertSession()->linkByHrefExists($display_option_url, 0, 'Make sure the option defined by the test display extender appears in the UI.');
+
+    $random_text = $this->randomMachineName();
+    $this->drupalGet($display_option_url);
+    $this->submitForm(['test_extender_test_option' => $random_text], 'Apply');
+    $this->assertSession()->linkExists($random_text);
+    $this->submitForm([], 'Save');
+    $view = Views::getView($view->storage->id());
+    $view->initDisplay();
+    $display_extender_options = $view->display_handler->getOption('display_extenders');
+    $this->assertEquals($random_text, $display_extender_options['display_extender_test']['test_extender_test_option'], 'Make sure that the display extender option got saved.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayFeedTest.php

@@ -0,0 +1,92 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the UI for feed display plugin.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\display\Feed
+ */
+class DisplayFeedTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_display_feed'];
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests feed display admin UI.
+   */
+  public function testFeedUI(): void {
+    // Test the RSS feed.
+    foreach (self::$testViews as $view_name) {
+      $this->checkFeedViewUi($view_name);
+    }
+  }
+
+  /**
+   * Checks views UI for a specific feed view.
+   *
+   * @param string $view_name
+   *   The view name to check against.
+   */
+  protected function checkFeedViewUi($view_name) {
+    $this->drupalGet('admin/structure/views');
+    // Verify that the page lists the $view_name view.
+    // Regression test: ViewListBuilder::getDisplayPaths() did not properly
+    // check whether a DisplayPluginCollection was returned in iterating over
+    // all displays.
+    $this->assertSession()->pageTextContains($view_name);
+
+    // Check the attach TO interface.
+    $this->drupalGet('admin/structure/views/nojs/display/' . $view_name . '/feed_1/displays');
+    // Display labels should be escaped.
+    $this->assertSession()->assertEscaped('<em>Page</em>');
+
+    // Load all the options of the checkbox.
+    $result = $this->xpath('//div[@id="edit-displays"]/div');
+    $options = [];
+    foreach ($result as $item) {
+      $input_node = $item->find('css', 'input');
+      if ($input_node->hasAttribute('value')) {
+        $options[] = $input_node->getAttribute('value');
+      }
+    }
+
+    $this->assertEquals(['default', 'page'], $options, 'Make sure all displays appears as expected.');
+
+    // Post and save this and check the output.
+    $this->drupalGet('admin/structure/views/nojs/display/' . $view_name . '/feed_1/displays');
+    $this->submitForm(['displays[page]' => 'page'], 'Apply');
+    // Options summary should be escaped.
+    $this->assertSession()->assertEscaped('<em>Page</em>');
+    $this->assertSession()->responseNotContains('<em>Page</em>');
+
+    $this->drupalGet('admin/structure/views/view/' . $view_name . '/edit/feed_1');
+    $this->assertSession()->elementTextContains('xpath', '//*[@id="views-feed-1-displays"]', 'Page');
+
+    // Add the default display, so there should now be multiple displays.
+    $this->drupalGet('admin/structure/views/nojs/display/' . $view_name . '/feed_1/displays');
+    $this->submitForm(['displays[default]' => 'default'], 'Apply');
+    $this->drupalGet('admin/structure/views/view/' . $view_name . '/edit/feed_1');
+    $this->assertSession()->elementTextContains('xpath', '//*[@id="views-feed-1-displays"]', 'Multiple displays');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayPathTest.php

@@ -0,0 +1,347 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Core\Menu\MenuTreeParameters;
+use Drupal\menu_link_content\Entity\MenuLinkContent;
+use Drupal\Tests\SchemaCheckTestTrait;
+use Drupal\Tests\system\Functional\Cache\AssertPageCacheContextsAndTagsTrait;
+
+/**
+ * Tests the UI of generic display path plugin.
+ *
+ * @group views_ui
+ * @group #slow
+ * @see \Drupal\views\Plugin\views\display\PathPluginBase
+ */
+class DisplayPathTest extends UITestBase {
+
+  use AssertPageCacheContextsAndTagsTrait;
+  use SchemaCheckTestTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->placeBlock('page_title_block');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view', 'test_page_display_menu'];
+
+  /**
+   * Runs the tests.
+   */
+  public function testPathUI(): void {
+    $this->doBasicPathUITest();
+    $this->doAdvancedPathsValidationTest();
+    $this->doPathXssFilterTest();
+  }
+
+  /**
+   * Tests basic functionality in configuring a view.
+   */
+  protected function doBasicPathUITest() {
+    $this->drupalGet('admin/structure/views/view/test_view');
+
+    // Add a new page display and check the appearing text.
+    $this->submitForm([], 'Add Page');
+    $this->assertSession()->pageTextContains('No path is set');
+    $this->assertSession()->linkNotExists('View page', 'No view page link found on the page.');
+
+    // Save a path and make sure the summary appears as expected.
+    $random_path = $this->randomMachineName();
+    // @todo Once https://www.drupal.org/node/2351379 is resolved, Views will no
+    //   longer use Url::fromUri(), and this path will be able to contain ':'.
+    $random_path = str_replace(':', '', $random_path);
+
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => $random_path], 'Apply');
+    $this->assertSession()->pageTextContains('/' . $random_path);
+    $this->clickLink('View Page');
+    $this->assertSession()->addressEquals($random_path);
+  }
+
+  /**
+   * Tests that View paths are properly filtered for XSS.
+   */
+  public function doPathXssFilterTest() {
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Add Page');
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_2/path');
+    $this->submitForm(['path' => '<object>malformed_path</object>'], 'Apply');
+    $this->submitForm([], 'Add Page');
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_3/path');
+    $this->submitForm(['path' => '<script>alert("hello");</script>'], 'Apply');
+    $this->submitForm([], 'Add Page');
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_4/path');
+    $this->submitForm(['path' => '<script>alert("hello I have placeholders %");</script>'], 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Save');
+    $this->drupalGet('admin/structure/views');
+    // The anchor text should be escaped.
+    $this->assertSession()->assertEscaped('/<object>malformed_path</object>');
+    $this->assertSession()->assertEscaped('/<script>alert("hello");</script>');
+    $this->assertSession()->assertEscaped('/<script>alert("hello I have placeholders %");</script>');
+    // Links should be URL-encoded.
+    $this->assertSession()->responseContains('/%3Cobject%3Emalformed_path%3C/object%3E');
+    $this->assertSession()->responseContains('/%3Cscript%3Ealert%28%22hello%22%29%3B%3C/script%3E');
+  }
+
+  /**
+   * Tests a couple of invalid path patterns.
+   */
+  protected function doAdvancedPathsValidationTest() {
+    $url = 'admin/structure/views/nojs/display/test_view/page_1/path';
+
+    $this->drupalGet($url);
+    $this->submitForm(['path' => '%/foo'], 'Apply');
+    $this->assertSession()->addressEquals($url);
+    $this->assertSession()->pageTextContains('"%" may not be used for the first segment of a path.');
+
+    $this->drupalGet($url);
+    $this->submitForm(['path' => 'user/%1/example'], 'Apply');
+    $this->assertSession()->addressEquals($url);
+    $this->assertSession()->pageTextContains("Numeric placeholders may not be used. Use plain placeholders (%).");
+  }
+
+  /**
+   * Tests deleting a page display that has no path.
+   */
+  public function testDeleteWithNoPath(): void {
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Add Page');
+    $this->submitForm([], 'Delete Page');
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains("The view Test view has been saved.");
+  }
+
+  /**
+   * Tests the menu and tab option form.
+   */
+  public function testMenuOptions(): void {
+    $this->drupalGet('admin/structure/views/view/test_view');
+
+    // Add a new page display.
+    $this->submitForm([], 'Add Page');
+
+    // Add an invalid path (only fragment).
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => '#foo'], 'Apply');
+    $this->assertSession()->pageTextContains('Path is empty');
+
+    // Add an invalid path with a query.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => 'foo?bar'], 'Apply');
+    $this->assertSession()->pageTextContains('No query allowed.');
+
+    // Add an invalid path with just a query.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => '?bar'], 'Apply');
+    $this->assertSession()->pageTextContains('Path is empty');
+
+    // Provide a random, valid path string.
+    $random_string = $this->randomMachineName();
+
+    // Save a path.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => $random_string], 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view');
+
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/menu');
+    $this->submitForm([
+      'menu[type]' => 'default tab',
+      'menu[title]' => 'Test tab title',
+    ], 'Apply');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->addressEquals('admin/structure/views/nojs/display/test_view/page_1/tab_options');
+
+    $this->submitForm(['tab_options[type]' => 'tab', 'tab_options[title]' => $this->randomString()], 'Apply');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_view/edit/page_1');
+
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->assertSession()->linkExists('Tab: Test tab title');
+    // If it's a default tab, it should also have an additional settings link.
+    $this->assertSession()->linkByHrefExists('admin/structure/views/nojs/display/test_view/page_1/tab_options');
+
+    // Ensure that you can select a parent in case the parent does not exist.
+    $this->drupalGet('admin/structure/views/nojs/display/test_page_display_menu/page_5/menu');
+    $this->assertSession()->statusCodeEquals(200);
+    $menu_options = $this->assertSession()->selectExists('edit-menu-parent')->findAll('css', 'option');
+    $menu_options = array_map(function ($element) {
+      return $element->getText();
+    }, $menu_options);
+
+    $this->assertEquals([
+      '<User account menu>',
+      '-- My account',
+      '-- Log out',
+      '<Administration>',
+      '<Footer>',
+      '<Main navigation>',
+      '<Tools>',
+      '-- Compose tips (disabled)',
+      '-- Test menu link',
+    ], $menu_options);
+
+    // The cache contexts associated with the (in)accessible menu links are
+    // bubbled.
+    $this->assertCacheContext('user.permissions');
+  }
+
+  /**
+   * Tests the regression in https://www.drupal.org/node/2532490.
+   */
+  public function testDefaultMenuTabRegression(): void {
+    $this->container->get('module_installer')->install(['menu_link_content', 'toolbar', 'system']);
+    $this->resetAll();
+    $admin_user = $this->drupalCreateUser([
+      'administer views',
+      'administer blocks',
+      'bypass node access',
+      'access user profiles',
+      'view all revisions',
+      'administer permissions',
+      'administer menu',
+      'link to any page',
+      'access toolbar',
+      'access administration pages',
+    ]);
+    $this->drupalLogin($admin_user);
+
+    $edit = [
+      'title[0][value]' => 'Menu title',
+      'link[0][uri]' => '/admin/foo',
+      'menu_parent' => 'admin:system.admin',
+    ];
+    $this->drupalGet('admin/structure/menu/manage/admin/add');
+    $this->submitForm($edit, 'Save');
+
+    $menu_items = \Drupal::entityTypeManager()->getStorage('menu_link_content')->getQuery()
+      ->accessCheck(FALSE)
+      ->sort('id', 'DESC')
+      ->pager(1)
+      ->execute();
+    $menu_item = end($menu_items);
+    /** @var \Drupal\menu_link_content\MenuLinkContentInterface $menu_link_content */
+    $menu_link_content = MenuLinkContent::load($menu_item);
+
+    $edit = [];
+    $edit['label'] = $this->randomMachineName(16);
+    $view_id = $edit['id'] = $this->randomMachineName(16);
+    $edit['description'] = $this->randomMachineName(16);
+    $edit['page[create]'] = TRUE;
+    $edit['page[path]'] = 'admin/foo';
+
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($edit, 'Save and edit');
+
+    $parameters = new MenuTreeParameters();
+    $parameters->addCondition('id', $menu_link_content->getPluginId());
+    $result = \Drupal::menuTree()->load('admin', $parameters);
+    $plugin_definition = end($result)->link->getPluginDefinition();
+    $this->assertEquals('view.' . $view_id . '.page_1', $plugin_definition['route_name']);
+
+    $this->clickLink('No menu');
+
+    $this->submitForm([
+      'menu[type]' => 'default tab',
+      'menu[title]' => 'Menu title',
+    ], 'Apply');
+
+    $this->assertSession()->pageTextContains('Default tab options');
+
+    $this->submitForm([
+      'tab_options[type]' => 'normal',
+      'tab_options[title]' => 'Parent title',
+    ], 'Apply');
+
+    // Open the menu options again.
+    $this->clickLink('Tab: Menu title');
+
+    // Assert a menu can be selected as a parent.
+    $this->assertSession()->optionExists('menu[parent]', 'admin:');
+
+    // Assert a parent menu item can be selected from within a menu.
+    $this->assertSession()->optionExists('menu[parent]', 'admin:system.admin');
+
+    // Check that parent menu item can now be
+    // added without the menu_ui module being enabled.
+    $this->submitForm([
+      'menu[type]' => 'normal',
+      'menu[parent]' => 'admin:system.admin',
+      'menu[title]' => 'Menu title',
+    ], 'Apply');
+
+    $this->submitForm([], 'Save');
+    // Assert that saving the view will not cause an exception.
+    $this->assertSession()->statusCodeEquals(200);
+  }
+
+  /**
+   * Tests the "Use the administration theme" configuration.
+   *
+   * @see \Drupal\Tests\views\Functional\Plugin\DisplayPageWebTest::testAdminTheme
+   */
+  public function testUseAdminTheme(): void {
+    $this->drupalGet('admin/structure/views/view/test_view');
+
+    // Add a new page display.
+    $this->submitForm([], 'Add Page');
+    $this->assertSession()->pageTextContains('No path is set');
+    $this->assertSession()->pageTextContains('Administration theme: No');
+
+    // Test with a path starting with "/admin".
+    $admin_path = 'admin/test_admin_path';
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => $admin_path], 'Apply');
+    $this->assertSession()->pageTextContains('/' . $admin_path);
+    $this->assertSession()->pageTextContains('Administration theme: Yes (admin path)');
+    $this->submitForm([], 'Save');
+
+    $this->assertConfigSchemaByName('views.view.test_view');
+    $display_options = $this->config('views.view.test_view')->get('display.page_1.display_options');
+    $this->assertArrayNotHasKey('use_admin_theme', $display_options);
+
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/use_admin_theme');
+    $this->assertSession()->elementExists('css', 'input[name="use_admin_theme"][disabled="disabled"][checked="checked"]');
+
+    // Test with a non-administration path.
+    $non_admin_path = 'kittens';
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => $non_admin_path], 'Apply');
+    $this->assertSession()->pageTextContains('/' . $non_admin_path);
+    $this->assertSession()->pageTextContains('Administration theme: No');
+    $this->submitForm([], 'Save');
+
+    $this->assertConfigSchemaByName('views.view.test_view');
+    $display_options = $this->config('views.view.test_view')->get('display.page_1.display_options');
+    $this->assertArrayNotHasKey('use_admin_theme', $display_options);
+
+    // Enable administration theme.
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/use_admin_theme');
+    $this->submitForm(['use_admin_theme' => TRUE], 'Apply');
+    $this->assertSession()->pageTextContains('Administration theme: Yes');
+    $this->submitForm([], 'Save');
+
+    $this->assertConfigSchemaByName('views.view.test_view');
+    $display_options = $this->config('views.view.test_view')->get('display.page_1.display_options');
+    $this->assertArrayHasKey('use_admin_theme', $display_options);
+    $this->assertTrue($display_options['use_admin_theme']);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DisplayTest.php

@@ -0,0 +1,308 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\views\Entity\View;
+use Drupal\views\Views;
+
+/**
+ * Tests the display UI.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class DisplayTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_display'];
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['contextual'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests adding a display.
+   */
+  public function testAddDisplay(): void {
+    $view = $this->randomView();
+    $this->assertSession()->elementNotExists('xpath', '//li[@data-drupal-selector="edit-displays-top-tabs-block-1"]');
+    $this->assertSession()->elementNotExists('xpath', '//li[@data-drupal-selector="edit-displays-top-tabs-block-2"]');
+    $this->assertSession()->pageTextMatchesCount(0, '/Block name:/');
+
+    $this->submitForm([], 'Add Block');
+    $this->assertSession()->elementTextContains('xpath', '//li[@data-drupal-selector="edit-displays-top-tabs-block-1"]', 'Block*');
+    $this->assertSession()->elementNotExists('xpath', '//li[@data-drupal-selector="edit-displays-top-tabs-block-2"]');
+    $this->assertSession()->pageTextMatchesCount(1, '/Block name:/');
+  }
+
+  /**
+   * Tests reordering of displays.
+   */
+  public function testReorderDisplay(): void {
+    $view = [
+      'block[create]' => TRUE,
+    ];
+    $view = $this->randomView($view);
+
+    $this->clickLink('Reorder displays');
+    $this->assertSession()->elementExists('xpath', '//tr[@id="display-row-default"]');
+    $this->assertSession()->elementExists('xpath', '//tr[@id="display-row-page_1"]');
+    $this->assertSession()->elementExists('xpath', '//tr[@id="display-row-block_1"]');
+
+    // Ensure the view displays are in the expected order in configuration.
+    $expected_display_order = ['default', 'block_1', 'page_1'];
+    $this->assertEquals($expected_display_order, array_keys(Views::getView($view['id'])->storage->get('display')), 'The correct display names are present.');
+    // Put the block display in front of the page display.
+    $edit = [
+      'displays[page_1][weight]' => 2,
+      'displays[block_1][weight]' => 1,
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+
+    $view = Views::getView($view['id']);
+    $displays = $view->storage->get('display');
+    $this->assertEquals(0, $displays['default']['position'], 'Make sure the default display comes first.');
+    $this->assertEquals(1, $displays['block_1']['position'], 'Make sure the block display comes before the page display.');
+    $this->assertEquals(2, $displays['page_1']['position'], 'Make sure the page display comes after the block display.');
+
+    // Ensure the view displays are in the expected order in configuration.
+    $this->assertEquals($expected_display_order, array_keys($view->storage->get('display')), 'The correct display names are present.');
+  }
+
+  /**
+   * Tests disabling of a display.
+   */
+  public function testDisableDisplay(): void {
+    $view = $this->randomView();
+    $path_prefix = 'admin/structure/views/view/' . $view['id'] . '/edit';
+
+    // Verify that the disabled display css class does not appear after initial
+    // adding of a view.
+    $this->drupalGet($path_prefix);
+    $this->assertSession()->elementNotExists('xpath', "//div[contains(@class, 'views-display-disabled')]");
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-disable');
+    $this->assertSession()->buttonNotExists('edit-displays-settings-settings-content-tab-content-details-top-actions-enable');
+
+    // Verify that the disabled display css class appears once the display is
+    // marked as such.
+    $this->submitForm([], 'Disable Page');
+    $this->assertSession()->elementExists('xpath', "//div[contains(@class, 'views-display-disabled')]");
+    $this->assertSession()->buttonNotExists('edit-displays-settings-settings-content-tab-content-details-top-actions-disable');
+    $this->assertSession()->buttonExists('edit-displays-settings-settings-content-tab-content-details-top-actions-enable');
+
+    // Verify that the disabled display css class does not appears once the
+    // display is enabled again.
+    $this->submitForm([], 'Enable Page');
+    $this->assertSession()->elementNotExists('xpath', "//div[contains(@class, 'views-display-disabled')]");
+  }
+
+  /**
+   * Tests views_ui_views_plugins_display_alter is altering plugin definitions.
+   */
+  public function testDisplayPluginsAlter(): void {
+    $definitions = Views::pluginManager('display')->getDefinitions();
+
+    $expected = [
+      'route_name' => 'entity.view.edit_form',
+      'route_parameters_names' => ['view' => 'id'],
+    ];
+
+    // Test the expected views_ui array exists on each definition.
+    foreach ($definitions as $definition) {
+      $this->assertSame($expected, $definition['contextual links']['entity.view.edit_form'], 'Expected views_ui array found in plugin definition.');
+    }
+  }
+
+  /**
+   * Tests display areas.
+   */
+  public function testDisplayAreas(): void {
+    // Show the advanced column.
+    $this->config('views.settings')->set('ui.show.advanced_column', TRUE)->save();
+
+    // Add a new data display to the view.
+    $view = Views::getView('test_display');
+    $view->storage->addDisplay('display_no_area_test');
+    $view->save();
+
+    $this->drupalGet('admin/structure/views/view/test_display/edit/display_no_area_test_1');
+
+    $areas = [
+      'header',
+      'footer',
+      'empty',
+    ];
+
+    // Assert that the expected text is found in each area category.
+    foreach ($areas as $type) {
+      $this->assertSession()->elementTextEquals('xpath', "//div[contains(@class, '$type')]/div", "The selected display type does not use $type plugins");
+    }
+  }
+
+  /**
+   * Tests the link-display setting.
+   */
+  public function testLinkDisplay(): void {
+    // Test setting the link display in the UI form.
+    $path = 'admin/structure/views/view/test_display/edit/block_1';
+    $link_display_path = 'admin/structure/views/nojs/display/test_display/block_1/link_display';
+
+    // Test the link text displays 'None' and not 'Block 1'
+    $this->drupalGet($path);
+    $this->assertSession()->elementTextEquals('xpath', "//a[contains(@href, '{$link_display_path}')]", 'None');
+
+    $this->drupalGet($link_display_path);
+    $this->assertSession()->checkboxChecked('edit-link-display-0');
+
+    // Test the default radio option on the link display form.
+    $this->drupalGet($link_display_path);
+    $this->submitForm(['link_display' => 'page_1'], 'Apply');
+    // The form redirects to the default display.
+    $this->drupalGet($path);
+
+    // Test that the link option summary shows the right linked display.
+    $this->assertSession()->elementTextEquals('xpath', "//a[contains(@href, '{$link_display_path}')]", 'Page');
+
+    $this->drupalGet($link_display_path);
+    $this->submitForm([
+      'link_display' => 'custom_url',
+      'link_url' => 'a-custom-url',
+    ], 'Apply');
+    // The form redirects to the default display.
+    $this->drupalGet($path);
+
+    $this->assertSession()->linkExists('Custom URL', 0, 'The link option has custom URL as summary.');
+
+    // Test the default link_url value for new display
+    $this->submitForm([], 'Add Block');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_display/edit/block_2');
+    $this->clickLink('Custom URL');
+    $this->assertSession()->fieldValueEquals('link_url', 'a-custom-url');
+  }
+
+  /**
+   * Tests that the view status is correctly reflected on the edit form.
+   */
+  public function testViewStatus(): void {
+    $view = $this->randomView();
+    $id = $view['id'];
+
+    // The view should initially have the enabled class on its form wrapper.
+    $this->drupalGet('admin/structure/views/view/' . $id);
+    $this->assertSession()->elementExists('xpath', "//div[contains(@class, 'views-edit-view') and contains(@class, 'enabled')]");
+
+    $view = Views::getView($id);
+    $view->storage->disable()->save();
+
+    // The view should now have the disabled class on its form wrapper.
+    $this->drupalGet('admin/structure/views/view/' . $id);
+    $this->assertSession()->elementExists('xpath', "//div[contains(@class, 'views-edit-view') and contains(@class, 'disabled')]");
+  }
+
+  /**
+   * Ensures that no XSS is possible for buttons.
+   */
+  public function testDisplayTitleInButtonsXss(): void {
+    $xss_markup = '"><script>alert(123)</script>';
+    $view = $this->randomView();
+    $view = View::load($view['id']);
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.show.default_display', TRUE)->save();
+
+    foreach ([$xss_markup, '&quot;><script>alert(123)</script>'] as $input) {
+      $display =& $view->getDisplay('page_1');
+      $display['display_title'] = $input;
+      $view->save();
+
+      $this->drupalGet("admin/structure/views/view/{$view->id()}");
+      $escaped = Unicode::truncate($input, 25, FALSE, TRUE);
+      $this->assertSession()->assertEscaped($escaped);
+      $this->assertSession()->responseNotContains($xss_markup);
+
+      $this->drupalGet("admin/structure/views/view/{$view->id()}/edit/page_1");
+      $this->assertSession()->assertEscaped("View $escaped");
+      $this->assertSession()->responseNotContains("View $xss_markup");
+      $this->assertSession()->assertEscaped("Duplicate $escaped");
+      $this->assertSession()->responseNotContains("Duplicate $xss_markup");
+      $this->assertSession()->assertEscaped("Delete $escaped");
+      $this->assertSession()->responseNotContains("Delete $xss_markup");
+    }
+  }
+
+  /**
+   * Tests the action links on the edit display UI.
+   */
+  public function testActionLinks(): void {
+    // Change the display title of a display so it contains characters that will
+    // be escaped when rendered.
+    $display_title = "'<test>'";
+    $this->drupalGet('admin/structure/views/view/test_display');
+    $display_title_path = 'admin/structure/views/nojs/display/test_display/block_1/display_title';
+    $this->drupalGet($display_title_path);
+    $this->submitForm(['display_title' => $display_title], 'Apply');
+
+    // Ensure that the title is escaped as expected.
+    $this->assertSession()->assertEscaped($display_title);
+    $this->assertSession()->responseNotContains($display_title);
+
+    // Ensure that the dropdown buttons are displayed correctly.
+    $this->assertSession()->buttonExists('Duplicate ' . $display_title);
+    $this->assertSession()->buttonExists('Delete ' . $display_title);
+    $this->assertSession()->buttonExists('Disable ' . $display_title);
+    $this->assertSession()->buttonNotExists('Enable ' . $display_title);
+
+    // Disable the display so we can test the rendering of the "Enable" button.
+    $this->submitForm([], 'Disable ' . $display_title);
+    $this->assertSession()->buttonExists('Enable ' . $display_title);
+    $this->assertSession()->buttonNotExists('Disable ' . $display_title);
+
+    // Ensure that the title is escaped as expected.
+    $this->assertSession()->assertEscaped($display_title);
+    $this->assertSession()->responseNotContains($display_title);
+  }
+
+  /**
+   * Tests that the override option is hidden when it's not needed.
+   */
+  public function testHideDisplayOverride(): void {
+    // Test that the override option appears with two displays.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_display/page_1/field/title');
+    $this->assertSession()->pageTextContains('All displays');
+
+    // Remove a display and test if the override option is hidden.
+    $this->drupalGet('admin/structure/views/view/test_display/edit/block_1');
+    $this->submitForm([], 'Delete Block');
+    $this->submitForm([], 'Save');
+
+    $this->drupalGet('admin/structure/views/nojs/handler/test_display/page_1/field/title');
+    $this->assertSession()->pageTextNotContains('All displays');
+
+    // Test that the override option is shown when default display is on.
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.show.default_display', TRUE)->save();
+    $this->drupalGet('admin/structure/views/nojs/handler/test_display/page_1/field/title');
+    $this->assertSession()->pageTextContains('All displays');
+
+    // Test that the override option is shown if the current display is
+    // overridden so that the option to revert is available.
+    $this->submitForm(['override[dropdown]' => 'page_1'], 'Apply');
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.show.default_display', FALSE)->save();
+    $this->drupalGet('admin/structure/views/nojs/handler/test_display/page_1/field/title');
+    $this->assertSession()->pageTextContains('Revert to default');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/DuplicateTest.php

@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\language\Entity\ConfigurableLanguage;
+
+/**
+ * Tests the UI for view duplicate tool.
+ *
+ * @group views_ui
+ */
+class DuplicateTest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['config_translation', 'locale', 'language'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->placeBlock('page_title_block');
+  }
+
+  /**
+   * Checks if duplicated view exists and has correct label.
+   */
+  public function testDuplicateView(): void {
+    $language_manager = $this->container->get('language_manager');
+    ConfigurableLanguage::createFromLangcode('nl')->save();
+
+    // Create random view.
+    $random_view = $this->randomView();
+
+    // Add a translation to the View.
+    $translation = $language_manager->getLanguageConfigOverride('nl', 'views.view.' . $random_view['id']);
+    $translation->setData(['label' => 'NL label']);
+    $translation->save();
+
+    // Initialize array for duplicated view.
+    $view = [];
+
+    // Generate random label and id for new view.
+    $view['label'] = $this->randomMachineName(255);
+    $view['id'] = $this->randomMachineName(128);
+
+    // Duplicate view.
+    $this->drupalGet('admin/structure/views/view/' . $random_view['id'] . '/duplicate');
+    $this->submitForm($view, 'Duplicate');
+
+    // Assert that the page URL is correct.
+    $this->assertSession()->addressEquals('admin/structure/views/view/' . $view['id']);
+
+    // Assert that the page title is correctly displayed.
+    $this->assertSession()->pageTextContains($view['label']);
+
+    $copy_translation = $language_manager->getLanguageConfigOverride('nl', 'views.view.' . $view['id']);
+    $this->assertEquals(['label' => 'NL label'], $copy_translation->get());
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ExposedFormUITest.php

@@ -0,0 +1,404 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Entity\View;
+
+/**
+ * Tests exposed forms UI functionality.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class ExposedFormUITest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_exposed_admin_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'views_ui',
+    'block',
+    'taxonomy',
+    'field_ui',
+    'datetime',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Array of error message strings raised by the grouped form.
+   *
+   * @var array
+   *
+   * @see FilterPluginBase::buildGroupValidate
+   */
+  protected $groupFormUiErrors = [];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->drupalCreateContentType(['type' => 'article']);
+    $this->drupalCreateContentType(['type' => 'page']);
+
+    // Create some random nodes.
+    for ($i = 0; $i < 5; $i++) {
+      $this->drupalCreateNode();
+    }
+
+    // Error strings used in the grouped filter form validation.
+    $this->groupFormUiErrors['missing_value'] = 'A value is required if the label for this item is defined.';
+    $this->groupFormUiErrors['missing_title'] = 'A label is required if the value for this item is defined.';
+    $this->groupFormUiErrors['missing_title_empty_operator'] = 'A label is required for the specified operator.';
+  }
+
+  /**
+   * Tests the admin interface of exposed filter and sort items.
+   */
+  public function testExposedAdminUi(): void {
+    $edit = [];
+
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    // Be sure that the button is called exposed.
+    $this->helperButtonHasLabel('edit-options-expose-button-button', 'Expose filter');
+
+    // The first time the filter UI is displayed, the operator and the
+    // value forms should be shown.
+    $this->assertSession()->fieldValueEquals('edit-options-operator-in', 'in');
+    $this->assertSession()->fieldValueEquals('edit-options-operator-not-in', 'in');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-page');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-article');
+
+    // Click the Expose filter button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm($edit, 'Expose filter');
+    // Check the label of the expose button.
+    $this->helperButtonHasLabel('edit-options-expose-button-button', 'Hide filter');
+
+    // After exposing the filter, Operator and Value should be still here.
+    $this->assertSession()->fieldValueEquals('edit-options-operator-in', 'in');
+    $this->assertSession()->fieldValueEquals('edit-options-operator-not-in', 'in');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-page');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-article');
+
+    // Check the validations of the filter handler.
+    $edit = [];
+    $edit['options[expose][identifier]'] = '';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('The identifier is required if the filter is exposed.');
+
+    $edit = [];
+    $edit['options[expose][identifier]'] = 'value';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('This identifier is not allowed.');
+
+    // Now check the sort criteria.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/sort/created');
+    $this->helperButtonHasLabel('edit-options-expose-button-button', 'Expose sort');
+    $this->assertSession()->fieldNotExists('edit-options-expose-label');
+    $this->assertSession()->fieldNotExists('Sort field identifier');
+
+    // Un-expose the filter.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Hide filter');
+
+    // After Un-exposing the filter, Operator and Value should be shown again.
+    $this->assertSession()->fieldValueEquals('edit-options-operator-in', 'in');
+    $this->assertSession()->fieldValueEquals('edit-options-operator-not-in', 'in');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-page');
+    $this->assertSession()->checkboxNotChecked('edit-options-value-article');
+
+    // Click the Expose sort button.
+    $edit = [];
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/sort/created');
+    $this->submitForm($edit, 'Expose sort');
+    // Check the label of the expose button.
+    $this->helperButtonHasLabel('edit-options-expose-button-button', 'Hide sort');
+    $this->assertSession()->fieldValueEquals('edit-options-expose-label', 'Authored on');
+    $this->assertSession()->fieldValueEquals('Sort field identifier', 'created');
+
+    // Test adding a new exposed sort criteria.
+    $view_id = $this->randomView()['id'];
+    $this->drupalGet("admin/structure/views/nojs/add-handler/$view_id/default/sort");
+    $this->submitForm(['name[node_field_data.created]' => 1], 'Add and configure sort criteria');
+    $this->assertSession()->fieldValueEquals('options[order]', 'ASC');
+    // Change the order and expose the sort.
+    $this->submitForm(['options[order]' => 'DESC'], 'Apply');
+    $this->drupalGet("admin/structure/views/nojs/handler/{$view_id}/default/sort/created");
+    $this->submitForm([], 'Expose sort');
+    $this->assertSession()->fieldValueEquals('options[order]', 'DESC');
+    $this->assertSession()->fieldValueEquals('options[expose][label]', 'Authored on');
+    $this->assertSession()->fieldValueEquals('Sort field identifier', 'created');
+
+    // Change the label and try with an empty identifier.
+    $edit = [
+      'options[expose][label]' => $this->randomString(),
+      'options[expose][field_identifier]' => '',
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('Sort field identifier field is required.');
+
+    // Try with an invalid identifiers.
+    $edit['options[expose][field_identifier]'] = 'abc&! ###08.';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('This identifier has illegal characters.');
+    $edit['options[expose][field_identifier]'] = '^abcde';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('This identifier has illegal characters.');
+
+    // Use a valid identifier.
+    $edit['options[expose][field_identifier]'] = $this->randomMachineName() . '_-~.';
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Check that the values were saved.
+    $display = View::load($view_id)->getDisplay('default');
+    $this->assertTrue($display['display_options']['sorts']['created']['exposed']);
+    $this->assertSame([
+      'label' => $edit['options[expose][label]'],
+      'field_identifier' => $edit['options[expose][field_identifier]'],
+    ], $display['display_options']['sorts']['created']['expose']);
+    $this->assertSame('DESC', $display['display_options']['sorts']['created']['order']);
+
+    // Test the identifier uniqueness.
+    $this->drupalGet("admin/structure/views/nojs/handler/{$view_id}/default/sort/created_1");
+    $this->submitForm([], 'Expose sort');
+    $this->submitForm([
+      'options[expose][field_identifier]' => $edit['options[expose][field_identifier]'],
+    ], 'Apply');
+    $this->assertSession()->pageTextContains('This identifier is already used by Content: Authored on sort handler.');
+  }
+
+  /**
+   * Tests the admin interface of exposed grouped filters.
+   */
+  public function testGroupedFilterAdminUi(): void {
+    $edit = [];
+
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+
+    // Click the Expose filter button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm($edit, 'Expose filter');
+    // Check the label of the grouped filters button.
+    $this->helperButtonHasLabel('edit-options-group-button-button', 'Grouped filters');
+
+    // Click the Grouped Filters button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Grouped filters');
+
+    // After click on 'Grouped Filters', the standard operator and value should
+    // not be displayed.
+    $this->assertSession()->fieldNotExists('edit-options-operator-in');
+    $this->assertSession()->fieldNotExists('edit-options-operator-not-in');
+    $this->assertSession()->fieldNotExists('edit-options-value-page');
+    $this->assertSession()->fieldNotExists('edit-options-value-article');
+
+    // Check that after click on 'Grouped Filters', a new button is shown to
+    // add more items to the list.
+    $this->helperButtonHasLabel('edit-options-group-info-add-group', 'Add another item');
+
+    // Validate a single entry for a grouped filter.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = 'Is Article';
+    $edit["options[group_info][group_items][1][value][article]"] = 'article';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_exposed_admin_ui/edit/default');
+    $this->assertNoGroupedFilterErrors();
+
+    // Validate multiple entries for grouped filters.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = 'Is Article';
+    $edit["options[group_info][group_items][1][value][article]"] = 'article';
+    $edit["options[group_info][group_items][2][title]"] = 'Is Page';
+    $edit["options[group_info][group_items][2][value][page]"] = 'page';
+    $edit["options[group_info][group_items][3][title]"] = 'Is Page and Article';
+    $edit["options[group_info][group_items][3][value][article]"] = 'article';
+    $edit["options[group_info][group_items][3][value][page]"] = 'page';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_exposed_admin_ui/edit/default');
+    $this->assertNoGroupedFilterErrors();
+
+    // Validate an "is empty" filter -- title without value is valid.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/body_value');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = 'No body';
+    $edit["options[group_info][group_items][1][operator]"] = 'empty';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_exposed_admin_ui/edit/default');
+    $this->assertNoGroupedFilterErrors();
+
+    // Ensure the string "0" can be used as a value for numeric filters.
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_exposed_admin_ui/default/filter');
+    $this->submitForm(['name[node_field_data.nid]' => TRUE], 'Add and configure filter criteria');
+    $this->submitForm([], 'Expose filter');
+    $this->submitForm([], 'Grouped filters');
+    $edit = [];
+    $edit['options[group_info][group_items][1][title]'] = 'Testing zero';
+    $edit['options[group_info][group_items][1][operator]'] = '>';
+    $edit['options[group_info][group_items][1][value][value]'] = '0';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_exposed_admin_ui/edit/default');
+    $this->assertNoGroupedFilterErrors();
+
+    // Ensure "between" filters validate correctly.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/nid');
+    $edit['options[group_info][group_items][1][title]'] = 'ID between test';
+    $edit['options[group_info][group_items][1][operator]'] = 'between';
+    $edit['options[group_info][group_items][1][value][min]'] = '0';
+    $edit['options[group_info][group_items][1][value][max]'] = '10';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_exposed_admin_ui/edit/default');
+    $this->assertNoGroupedFilterErrors();
+  }
+
+  public function testGroupedFilterAdminUiErrors(): void {
+    // Select the empty operator without a title specified.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/body_value');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = '';
+    $edit["options[group_info][group_items][1][operator]"] = 'empty';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains($this->groupFormUiErrors['missing_title_empty_operator']);
+
+    // Specify a title without a value.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Expose filter');
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Grouped filters');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = 'Is Article';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains($this->groupFormUiErrors['missing_value']);
+
+    // Specify a value without a title.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $edit = [];
+    $edit["options[group_info][group_items][1][title]"] = '';
+    $edit["options[group_info][group_items][1][value][article]"] = 'article';
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains($this->groupFormUiErrors['missing_title']);
+  }
+
+  /**
+   * Asserts that there are no Grouped Filters errors.
+   *
+   * @param string $message
+   *   The assert message.
+   *
+   * @internal
+   */
+  protected function assertNoGroupedFilterErrors(string $message = ''): void {
+    foreach ($this->groupFormUiErrors as $error) {
+      if (empty($message)) {
+        $this->assertSession()->responseNotContains($error);
+      }
+    }
+  }
+
+  /**
+   * Tests the configuration of grouped exposed filters.
+   */
+  public function testExposedGroupedFilter(): void {
+    // Click the Expose filter button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Expose filter');
+    // Select 'Grouped filters' radio button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $this->submitForm([], 'Grouped filters');
+    // Add 3 groupings.
+    $edit = [
+      'options[group_button][radios][radios]' => 1,
+      'options[group_info][group_items][1][title]' => '1st',
+      'options[group_info][group_items][1][value][all]' => 'all',
+      'options[group_info][group_items][2][title]' => '2nd',
+      'options[group_info][group_items][2][value][article]' => 'article',
+      'options[group_info][group_items][3][title]' => '3rd',
+      'options[group_info][group_items][3][value][page]' => 'page',
+      'options[group_info][default_group]' => '3',
+    ];
+    // Apply the filter settings.
+    $this->submitForm($edit, 'Apply');
+    // Check that the view is saved without errors.
+    $this->submitForm([], 'Save');
+    $this->assertSession()->statusCodeEquals(200);
+    // Check the default filter value.
+    $this->drupalGet('test_exposed_admin_ui');
+    $this->assertSession()->fieldValueEquals('type', '3');
+    // Enable "Allow multiple selections" option and set a default group.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/type');
+    $edit['options[group_info][multiple]'] = 1;
+    $edit['options[group_info][default_group_multiple][1]'] = 1;
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+    // Check the default filter values again.
+    $this->drupalGet('test_exposed_admin_ui');
+    $this->assertSession()->checkboxChecked('type[1]');
+    $this->assertSession()->checkboxNotChecked('type[2]');
+    $this->assertSession()->checkboxNotChecked('type[3]');
+
+    // Click the Expose filter button.
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_exposed_admin_ui/default/filter');
+    $this->submitForm(['name[node_field_data.status]' => 1], 'Add and configure filter criteria');
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/status');
+    $this->submitForm([], 'Expose filter');
+    // Select 'Grouped filters' radio button.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/status');
+    $this->submitForm([], 'Grouped filters');
+    // Add 3 groupings.
+    $edit = [
+      'options[group_button][radios][radios]' => 1,
+      'options[group_info][group_items][1][title]' => 'Any',
+      'options[group_info][group_items][1][value]' => 'All',
+      'options[group_info][group_items][2][title]' => 'Published',
+      'options[group_info][group_items][2][value]' => 1,
+      'options[group_info][group_items][3][title]' => 'Unpublished',
+      'options[group_info][group_items][3][value]' => 0,
+      'options[group_info][default_group]' => 2,
+    ];
+    // Apply the filter settings.
+    $this->submitForm($edit, 'Apply');
+    // Check that the view is saved without errors.
+    $this->submitForm([], 'Save');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/status');
+    // Assert the same settings defined before still are there.
+    $this->assertSession()->checkboxChecked('edit-options-group-info-group-items-1-value-all');
+    $this->assertSession()->checkboxChecked('edit-options-group-info-group-items-2-value-1');
+    $this->assertSession()->checkboxChecked('edit-options-group-info-group-items-3-value-0');
+
+    // Check the default filter value.
+    $this->drupalGet('test_exposed_admin_ui');
+    $this->assertSession()->fieldValueEquals('status', '2');
+    // Enable "Allow multiple selections" option and set a default group.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_exposed_admin_ui/default/filter/status');
+    $edit['options[group_info][multiple]'] = 1;
+    $edit['options[group_info][default_group_multiple][3]'] = 1;
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+    // Check the default filter value again.
+    $this->drupalGet('test_exposed_admin_ui');
+    $this->assertSession()->checkboxNotChecked('status[1]');
+    $this->assertSession()->checkboxNotChecked('status[2]');
+    $this->assertSession()->checkboxChecked('status[3]');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/FieldUITest.php

@@ -0,0 +1,107 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Component\Serialization\Json;
+use Drupal\views\Views;
+
+/**
+ * Tests the UI of field handlers.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\field\FieldPluginBase
+ */
+class FieldUITest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * Tests the UI of field handlers.
+   */
+  public function testFieldUI(): void {
+    // Ensure the field is not marked as hidden on the first run.
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    $this->assertSession()->pageTextContains('Views test: Name');
+    $this->assertSession()->pageTextNotContains('Views test: Name [hidden]');
+
+    // Hides the field and check whether the hidden label is appended.
+    $edit_handler_url = 'admin/structure/views/nojs/handler/test_view/default/field/name';
+    $this->drupalGet($edit_handler_url);
+    $this->submitForm(['options[exclude]' => TRUE], 'Apply');
+
+    $this->assertSession()->pageTextContains('Views test: Name [hidden]');
+
+    // Ensure that the expected tokens appear in the UI.
+    $edit_handler_url = 'admin/structure/views/nojs/handler/test_view/default/field/age';
+    $this->drupalGet($edit_handler_url);
+    $xpath = '//details[@id="edit-options-alter-help"]/ul/li';
+    $this->assertSession()->elementTextEquals('xpath', $xpath, '{{ age }} == Age');
+
+    $edit_handler_url = 'admin/structure/views/nojs/handler/test_view/default/field/id';
+    $this->drupalGet($edit_handler_url);
+    $this->assertSession()->elementTextEquals('xpath', "{$xpath}[1]", '{{ age }} == Age');
+    $this->assertSession()->elementTextEquals('xpath', "{$xpath}[2]", '{{ id }} == ID');
+
+    $edit_handler_url = 'admin/structure/views/nojs/handler/test_view/default/field/name';
+    $this->drupalGet($edit_handler_url);
+    $this->assertSession()->elementTextEquals('xpath', "{$xpath}[1]", '{{ age }} == Age');
+    $this->assertSession()->elementTextEquals('xpath', "{$xpath}[2]", '{{ id }} == ID');
+    $this->assertSession()->elementTextEquals('xpath', "{$xpath}[3]", '{{ name }} == Name');
+
+    $this->assertSession()->elementNotExists('xpath', '//details[@id="edit-options-more"]');
+
+    // Ensure that dialog titles are not escaped.
+    $edit_groupby_url = 'admin/structure/views/nojs/handler/test_view/default/field/name';
+    $this->assertSession()->linkByHrefNotExists($edit_groupby_url, 0, 'No aggregation link found.');
+
+    // Enable aggregation on the view.
+    $edit = [
+      'group_by' => TRUE,
+    ];
+    $this->drupalGet('/admin/structure/views/nojs/display/test_view/default/group_by');
+    $this->submitForm($edit, 'Apply');
+
+    $this->assertSession()->linkByHrefExists($edit_groupby_url, 0, 'Aggregation link found.');
+
+    $edit_handler_url = '/admin/structure/views/ajax/handler-group/test_view/default/field/name';
+    $this->drupalGet($edit_handler_url);
+    $data = Json::decode($this->getSession()->getPage()->getContent());
+    $this->assertEquals('Configure aggregation settings for field Views test: Name', $data[3]['dialogOptions']['title']);
+  }
+
+  /**
+   * Tests the field labels.
+   */
+  public function testFieldLabel(): void {
+    // Create a view with unformatted style and make sure the fields have no
+    // labels by default.
+    $view = [];
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['description'] = $this->randomMachineName(16);
+    $view['show[wizard_key]'] = 'node';
+    $view['page[create]'] = TRUE;
+    $view['page[style][style_plugin]'] = 'default';
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $view['id'];
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    $view = Views::getView($view['id']);
+    $view->initHandlers();
+    $this->assertEquals('', $view->field['title']->options['label'], 'The field label for normal styles are empty.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/FilterBooleanWebTest.php

@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the boolean filter UI.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\filter\BooleanOperator
+ */
+class FilterBooleanWebTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the filter boolean UI.
+   */
+  public function testFilterBooleanUI(): void {
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_view/default/filter');
+    $this->submitForm(['name[views_test_data.status]' => TRUE], 'Add and configure filter criteria');
+
+    // Check the field widget label. 'title' should be used as a fallback.
+    $result = $this->cssSelect('#edit-options-value--wrapper legend span');
+    $this->assertEquals('Status', $result[0]->getHtml());
+
+    // Ensure that the operator and the filter value are displayed using correct
+    // layout.
+    $this->assertSession()->elementExists('css', '.views-left-30 .form-item-options-operator');
+    $this->assertSession()->elementExists('css', '.views-right-70 .form-item-options-value');
+
+    $this->submitForm([], 'Expose filter');
+    $this->submitForm([], 'Grouped filters');
+
+    $edit = [];
+    $edit['options[group_info][group_items][1][title]'] = 'Published';
+    $edit['options[group_info][group_items][1][operator]'] = '=';
+    $edit['options[group_info][group_items][1][value]'] = 1;
+    $edit['options[group_info][group_items][2][title]'] = 'Not published';
+    $edit['options[group_info][group_items][2][operator]'] = '=';
+    $edit['options[group_info][group_items][2][value]'] = 0;
+    $edit['options[group_info][group_items][3][title]'] = 'Not published2';
+    $edit['options[group_info][group_items][3][operator]'] = '!=';
+    $edit['options[group_info][group_items][3][value]'] = 1;
+
+    $this->submitForm($edit, 'Apply');
+
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/status');
+
+    $result = $this->xpath('//input[@name="options[group_info][group_items][1][value]"]');
+    $this->assertEquals('checked', $result[1]->getAttribute('checked'));
+    $result = $this->xpath('//input[@name="options[group_info][group_items][2][value]"]');
+    $this->assertEquals('checked', $result[2]->getAttribute('checked'));
+    $result = $this->xpath('//input[@name="options[group_info][group_items][3][value]"]');
+    $this->assertEquals('checked', $result[1]->getAttribute('checked'));
+
+    // Test that there is a remove link for each group.
+    $this->assertCount(3, $this->cssSelect('a.views-remove-link'));
+
+    // Test selecting a default and removing an item.
+    $edit = [];
+    $edit['options[group_info][default_group]'] = 2;
+    $edit['options[group_info][group_items][3][remove]'] = 1;
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/status');
+    $this->assertSession()->fieldValueEquals('options[group_info][default_group]', 2);
+    $this->assertSession()->fieldNotExists('options[group_info][group_items][3][remove]');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/FilterNumericWebTest.php

@@ -0,0 +1,152 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Tests\SchemaCheckTestTrait;
+
+/**
+ * Tests the numeric filter UI.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\filter\NumericFilter
+ */
+class FilterNumericWebTest extends UITestBase {
+  use SchemaCheckTestTrait;
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the filter numeric UI.
+   */
+  public function testFilterNumericUI(): void {
+    // Add a page display to the test_view to be able to test the filtering.
+    $path = 'test_view-path';
+    $this->drupalGet('admin/structure/views/view/test_view/edit');
+    $this->submitForm([], 'Add Page');
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/page_1/path');
+    $this->submitForm(['path' => $path], 'Apply');
+    $this->submitForm([], 'Save');
+
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_view/default/filter');
+    $this->submitForm(['name[views_test_data.age]' => TRUE], 'Add and configure filter criteria');
+
+    $this->submitForm([], 'Expose filter');
+    $this->submitForm([], 'Grouped filters');
+
+    $edit = [];
+    $edit['options[group_info][group_items][1][title]'] = 'Old';
+    $edit['options[group_info][group_items][1][operator]'] = '>';
+    $edit['options[group_info][group_items][1][value][value]'] = 27;
+    $edit['options[group_info][group_items][2][title]'] = 'Young';
+    $edit['options[group_info][group_items][2][operator]'] = '<=';
+    $edit['options[group_info][group_items][2][value][value]'] = 27;
+    $edit['options[group_info][group_items][3][title]'] = 'From 26 to 28';
+    $edit['options[group_info][group_items][3][operator]'] = 'between';
+    $edit['options[group_info][group_items][3][value][min]'] = 26;
+    $edit['options[group_info][group_items][3][value][max]'] = 28;
+
+    $this->submitForm($edit, 'Apply');
+
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/age');
+    foreach ($edit as $name => $value) {
+      $this->assertSession()->fieldValueEquals($name, $value);
+    }
+
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Save');
+    $this->assertConfigSchemaByName('views.view.test_view');
+
+    // Test that the exposed filter works as expected.
+    $this->drupalGet('test_view-path');
+    $this->assertSession()->pageTextContains('John');
+    $this->assertSession()->pageTextContains('Paul');
+    $this->assertSession()->pageTextContains('Ringo');
+    $this->assertSession()->pageTextContains('George');
+    $this->assertSession()->pageTextContains('Meredith');
+    $this->submitForm(['age' => '2'], 'Apply');
+    $this->assertSession()->pageTextContains('John');
+    $this->assertSession()->pageTextContains('Paul');
+    $this->assertSession()->pageTextNotContains('Ringo');
+    $this->assertSession()->pageTextContains('George');
+    $this->assertSession()->pageTextNotContains('Meredith');
+
+    // Change the filter to a single filter to test the schema when the operator
+    // is not exposed.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/age');
+    $this->submitForm([], 'Single filter');
+    $edit = [];
+    $edit['options[value][value]'] = 25;
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Save');
+    $this->assertConfigSchemaByName('views.view.test_view');
+
+    // Test that the filter works as expected.
+    $this->drupalGet('test_view-path');
+    $this->assertSession()->pageTextContains('John');
+    $this->assertSession()->pageTextNotContains('Paul');
+    $this->assertSession()->pageTextNotContains('Ringo');
+    $this->assertSession()->pageTextNotContains('George');
+    $this->assertSession()->pageTextNotContains('Meredith');
+    $this->submitForm(['age' => '26'], 'Apply');
+    $this->assertSession()->pageTextNotContains('John');
+    $this->assertSession()->pageTextContains('Paul');
+    $this->assertSession()->pageTextNotContains('Ringo');
+    $this->assertSession()->pageTextNotContains('George');
+    $this->assertSession()->pageTextNotContains('Meredith');
+
+    // Change the filter to a 'between' filter to test if the label and
+    // description are set for the 'minimum' filter element.
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/age');
+    $edit = [];
+    $edit['options[expose][label]'] = 'Age between';
+    $edit['options[expose][description]'] = 'Description of the exposed filter';
+    $edit['options[operator]'] = 'between';
+    $edit['options[value][min]'] = 26;
+    $edit['options[value][max]'] = 28;
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Save');
+    $this->assertConfigSchemaByName('views.view.test_view');
+
+    $this->submitForm([], 'Update preview');
+    // Check the field (wrapper) label.
+    $this->assertSession()->elementTextContains('css', 'fieldset#edit-age-wrapper legend', 'Age between');
+    // Check the min/max labels.
+    $this->assertSession()->elementsCount('xpath', '//fieldset[contains(@id, "edit-age-wrapper")]//label[contains(@for, "edit-age-min") and contains(text(), "Min")]', 1);
+    $this->assertSession()->elementsCount('xpath', '//fieldset[contains(@id, "edit-age-wrapper")]//label[contains(@for, "edit-age-max") and contains(text(), "Max")]', 1);
+    // Check that the description is shown in the right place.
+    $this->assertEquals('Description of the exposed filter', trim($this->cssSelect('#edit-age-wrapper--description')[0]->getText()));
+
+    // Change to an operation that only requires one form element ('>').
+    $this->drupalGet('admin/structure/views/nojs/handler/test_view/default/filter/age');
+    $edit = [];
+    $edit['options[expose][label]'] = 'Age greater than';
+    $edit['options[expose][description]'] = 'Description of the exposed filter';
+    $edit['options[operator]'] = '>';
+    $edit['options[value][value]'] = 1000;
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->submitForm([], 'Save');
+    $this->assertConfigSchemaByName('views.view.test_view');
+
+    $this->submitForm([], 'Update preview');
+
+    // Make sure the label is visible and that there's no fieldset wrapper.
+    $this->assertSession()->elementsCount('xpath', '//label[contains(@for, "edit-age") and contains(text(), "Age greater than")]', 1);
+    $this->assertSession()->elementNotExists('xpath', '//fieldset[contains(@id, "edit-age-wrapper")]');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/FilterUITest.php

@@ -0,0 +1,142 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests for the filters from the UI.
+ *
+ * @group views_ui
+ */
+class FilterUITest extends UITestBase {
+
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_filter_in_operator_ui', 'test_filter_groups'];
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views_ui', 'node'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+    $this->drupalCreateContentType(['type' => 'page']);
+  }
+
+  /**
+   * Tests that an option for a filter is saved as expected from the UI.
+   */
+  public function testFilterInOperatorUi(): void {
+    $admin_user = $this->drupalCreateUser([
+      'administer views',
+      'administer site configuration',
+    ]);
+    $this->drupalLogin($admin_user);
+
+    $path = 'admin/structure/views/nojs/handler/test_filter_in_operator_ui/default/filter/type';
+    $this->drupalGet($path);
+    // Verifies that "Limit list to selected items" option is not selected.
+    $this->assertSession()->fieldValueEquals('options[expose][reduce]', FALSE);
+
+    // Select "Limit list to selected items" option and apply.
+    $edit = [
+      'options[expose][reduce]' => TRUE,
+    ];
+    $this->drupalGet($path);
+    $this->submitForm($edit, 'Apply');
+
+    // Verifies that the option was saved as expected.
+    $this->drupalGet($path);
+    $this->assertSession()->fieldValueEquals('options[expose][reduce]', TRUE);
+  }
+
+  /**
+   * Tests the filters from the UI.
+   */
+  public function testFiltersUI(): void {
+    $admin_user = $this->drupalCreateUser([
+      'administer views',
+      'administer site configuration',
+    ]);
+    $this->drupalLogin($admin_user);
+
+    $this->drupalGet('admin/structure/views/view/test_filter_groups');
+
+    $this->assertSession()->linkExists('Content: ID (= 1)', 0, 'Content: ID (= 1) link appears correctly.');
+
+    // Tests that we can create a new filter group from UI.
+    $this->drupalGet('admin/structure/views/nojs/rearrange-filter/test_filter_groups/page');
+    $this->assertSession()->elementNotExists('xpath', '//span[text()="Group 3"]');
+
+    // Create 2 new groups.
+    $this->submitForm([], 'Create new filter group');
+    $this->submitForm([], 'Create new filter group');
+
+    // Remove the new group 3.
+    $this->submitForm([], 'Remove group 3');
+
+    // Verify that the group 4 is now named as 3.
+    $this->assertSession()->responseContains('<span>Group 3</span>');
+
+    // Remove the group 3 again.
+    $this->submitForm([], 'Remove group 3');
+
+    // Group 3 now does not exist.
+    $this->assertSession()->elementNotExists('xpath', '//span[text()="Group 3"]');
+  }
+
+  /**
+   * Tests the identifier settings and restrictions.
+   */
+  public function testFilterIdentifier(): void {
+    $admin_user = $this->drupalCreateUser([
+      'administer views',
+      'administer site configuration',
+    ]);
+    $this->drupalLogin($admin_user);
+    $path = 'admin/structure/views/nojs/handler/test_filter_in_operator_ui/default/filter/type';
+
+    // Set an empty identifier.
+    $edit = [
+      'options[expose][identifier]' => '',
+    ];
+    $this->drupalGet($path);
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('The identifier is required if the filter is exposed.');
+
+    // Set the identifier to 'value'.
+    $edit = [
+      'options[expose][identifier]' => 'value',
+    ];
+    $this->drupalGet($path);
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('This identifier is not allowed.');
+
+    // Try a few restricted values for the identifier.
+    foreach (['value value', 'value^value'] as $identifier) {
+      $edit = [
+        'options[expose][identifier]' => $identifier,
+      ];
+      $this->drupalGet($path);
+      $this->submitForm($edit, 'Apply');
+      $this->assertSession()->pageTextContains('This identifier has illegal characters.');
+    }
+  }
+
+}

core/modules/views_ui/tests/src/Functional/GenericTest.php

@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Tests\system\Functional\Module\GenericModuleTestBase;
+
+/**
+ * Generic module test for views_ui.
+ *
+ * @group views_ui
+ */
+class GenericTest extends GenericModuleTestBase {}

core/modules/views_ui/tests/src/Functional/GroupByTest.php

@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests UI of aggregate functionality..
+ *
+ * @group views_ui
+ */
+class GroupByTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_views_groupby_save'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests whether basic saving works.
+   *
+   * @todo This should check the change of the settings as well.
+   */
+  public function testGroupBySave(): void {
+    $this->drupalGet('admin/structure/views/view/test_views_groupby_save/edit');
+
+    $edit_groupby_url = 'admin/structure/views/nojs/handler-group/test_views_groupby_save/default/field/id';
+    $this->assertSession()->linkByHrefNotExists($edit_groupby_url, 0, 'No aggregation link found.');
+
+    // Enable aggregation on the view.
+    $edit = [
+      'group_by' => TRUE,
+    ];
+    $this->drupalGet('admin/structure/views/nojs/display/test_views_groupby_save/default/group_by');
+    $this->submitForm($edit, 'Apply');
+
+    $this->assertSession()->linkByHrefExists($edit_groupby_url, 0, 'Aggregation link found.');
+
+    // Change the groupby type in the UI.
+    $this->drupalGet($edit_groupby_url);
+    $this->submitForm(['options[group_type]' => 'count'], 'Apply');
+    $this->assertSession()->linkExists('COUNT(Views test: ID)', 0, 'The count setting is displayed in the UI');
+
+    $this->submitForm([], 'Save');
+
+    $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_views_groupby_save');
+    $display = $view->getDisplay('default');
+    $this->assertTrue($display['display_options']['group_by'], 'The groupby setting was saved on the view.');
+    $this->assertEquals('count', $display['display_options']['fields']['id']['group_type'], 'Count groupby_type was saved on the view.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/HandlerTest.php

@@ -0,0 +1,307 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+use Drupal\views\Tests\ViewTestData;
+use Drupal\views\ViewExecutable;
+
+/**
+ * Tests handler UI for views.
+ *
+ * @group views_ui
+ * @group #slow
+ * @see \Drupal\views\Plugin\views\HandlerBase
+ */
+class HandlerTest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['node_test_views'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view_empty', 'test_view_broken', 'node', 'test_node_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->placeBlock('page_title_block');
+    ViewTestData::createTestViews(static::class, ['node_test_views']);
+  }
+
+  /**
+   * Overrides \Drupal\views\Tests\ViewTestBase::schemaDefinition().
+   *
+   * Adds a uid column to test the relationships.
+   *
+   * @internal
+   */
+  protected function schemaDefinition() {
+    $schema = parent::schemaDefinition();
+
+    $schema['views_test_data']['fields']['uid'] = [
+      'description' => "The {users}.uid of the author of the beatle entry.",
+      'type' => 'int',
+      'unsigned' => TRUE,
+      'not null' => TRUE,
+      'default' => 0,
+    ];
+
+    return $schema;
+  }
+
+  /**
+   * Overrides \Drupal\views\Tests\ViewTestBase::viewsData().
+   *
+   * Adds:
+   * - a relationship for the uid column.
+   * - a dummy field with no help text.
+   */
+  protected function viewsData() {
+    $data = parent::viewsData();
+    $data['views_test_data']['uid'] = [
+      'title' => 'UID',
+      'help' => 'The test data UID',
+      'relationship' => [
+        'id' => 'standard',
+        'base' => 'users_field_data',
+        'base field' => 'uid',
+      ],
+    ];
+
+    // Create a dummy field with no help text.
+    $data['views_test_data']['no_help'] = $data['views_test_data']['name'];
+    $data['views_test_data']['no_help']['field']['title'] = 'No help';
+    $data['views_test_data']['no_help']['field']['real field'] = 'name';
+    unset($data['views_test_data']['no_help']['help']);
+
+    return $data;
+  }
+
+  /**
+   * Tests UI CRUD.
+   */
+  public function testUiCrud(): void {
+    $handler_types = ViewExecutable::getHandlerTypes();
+    foreach ($handler_types as $type => $type_info) {
+      // Test adding handlers.
+      $add_handler_url = "admin/structure/views/nojs/add-handler/test_view_empty/default/$type";
+
+      // Area handler types need to use a different handler.
+      if (in_array($type, ['header', 'footer', 'empty'])) {
+        $this->drupalGet($add_handler_url);
+        $this->submitForm([
+          'name[views.area]' => TRUE,
+        ], 'Add and configure ' . $type_info['ltitle']);
+        $id = 'area';
+        $edit_handler_url = "admin/structure/views/nojs/handler/test_view_empty/default/$type/$id";
+      }
+      elseif ($type == 'relationship') {
+        $this->drupalGet($add_handler_url);
+        $this->submitForm([
+          'name[views_test_data.uid]' => TRUE,
+        ], 'Add and configure ' . $type_info['ltitle']);
+        $id = 'uid';
+        $edit_handler_url = "admin/structure/views/nojs/handler/test_view_empty/default/$type/$id";
+      }
+      else {
+        $this->drupalGet($add_handler_url);
+        $this->submitForm([
+          'name[views_test_data.job]' => TRUE,
+        ], 'Add and configure ' . $type_info['ltitle']);
+        $id = 'job';
+        $edit_handler_url = "admin/structure/views/nojs/handler/test_view_empty/default/$type/$id";
+      }
+
+      // Verify that the user got redirected to the handler edit form.
+      $this->assertSession()->addressEquals($edit_handler_url);
+      $random_label = $this->randomMachineName();
+      $this->submitForm(['options[admin_label]' => $random_label], 'Apply');
+
+      // Verify that the user got redirected to the views edit form.
+      $this->assertSession()->addressEquals('admin/structure/views/view/test_view_empty/edit/default');
+      $this->assertSession()->linkByHrefExists($edit_handler_url, 0, 'The handler edit link appears in the UI.');
+      // Test that the  handler edit link has the right label.
+      $this->assertSession()->elementExists('xpath', "//a[starts-with(normalize-space(text()), '{$random_label}')]");
+
+      // Save the view and have a look whether the handler was added as expected.
+      $this->submitForm([], 'Save');
+      $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_view_empty');
+      $display = $view->getDisplay('default');
+      $this->assertTrue(isset($display['display_options'][$type_info['plural']][$id]), 'Ensure the field was added to the view itself.');
+
+      // Remove the item and check that it's removed
+      $this->drupalGet($edit_handler_url);
+      $this->submitForm([], 'Remove');
+      $this->assertSession()->linkByHrefNotExists($edit_handler_url, 0, 'The handler edit link does not appears in the UI after removing.');
+
+      $this->submitForm([], 'Save');
+      $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_view_empty');
+      $display = $view->getDisplay('default');
+      $this->assertFalse(isset($display['display_options'][$type_info['plural']][$id]), 'Ensure the field was removed from the view itself.');
+    }
+
+    // Test adding a field of the user table using the uid relationship.
+    $type_info = $handler_types['relationship'];
+    $add_handler_url = "admin/structure/views/nojs/add-handler/test_view_empty/default/relationship";
+    $this->drupalGet($add_handler_url);
+    $this->submitForm([
+      'name[views_test_data.uid]' => TRUE,
+    ], 'Add and configure ' . $type_info['ltitle']);
+
+    $add_handler_url = "admin/structure/views/nojs/add-handler/test_view_empty/default/field";
+    $type_info = $handler_types['field'];
+    $this->drupalGet($add_handler_url);
+    $this->submitForm([
+      'name[users_field_data.name]' => TRUE,
+    ], 'Add and configure ' . $type_info['ltitle']);
+    $id = 'name';
+    $edit_handler_url = "admin/structure/views/nojs/handler/test_view_empty/default/field/$id";
+
+    // Verify that the user got redirected to the handler edit form.
+    $this->assertSession()->addressEquals($edit_handler_url);
+    $this->assertSession()->fieldValueEquals('options[relationship]', 'uid');
+    $this->submitForm([], 'Apply');
+
+    $this->submitForm([], 'Save');
+    $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_view_empty');
+    $display = $view->getDisplay('default');
+    $this->assertTrue(isset($display['display_options'][$type_info['plural']][$id]), 'Ensure the field was added to the view itself.');
+  }
+
+  /**
+   * Tests escaping of field labels in help text.
+   */
+  public function testHandlerHelpEscaping(): void {
+    // Setup a field with two instances using a different label.
+    // Ensure that the label is escaped properly.
+
+    $this->drupalCreateContentType(['type' => 'article']);
+    $this->drupalCreateContentType(['type' => 'page']);
+
+    FieldStorageConfig::create([
+      'field_name' => 'field_test',
+      'entity_type' => 'node',
+      'type' => 'string',
+    ])->save();
+
+    FieldConfig::create([
+      'field_name' => 'field_test',
+      'entity_type' => 'node',
+      'bundle' => 'page',
+      'label' => 'The giraffe" label',
+    ])->save();
+
+    FieldConfig::create([
+      'field_name' => 'field_test',
+      'entity_type' => 'node',
+      'bundle' => 'article',
+      'label' => 'The <em>giraffe"</em> label <script>alert("the return of the xss")</script>',
+    ])->save();
+
+    $this->drupalGet('admin/structure/views/nojs/add-handler/content/default/field');
+    $this->assertSession()->assertEscaped('The <em>giraffe"</em> label <script>alert("the return of the xss")</script>');
+    $this->assertSession()->assertEscaped('Appears in: page, article. Also known as: Content: The giraffe" label');
+  }
+
+  /**
+   * Tests broken handlers.
+   */
+  public function testBrokenHandlers(): void {
+    $handler_types = ViewExecutable::getHandlerTypes();
+    foreach ($handler_types as $type => $type_info) {
+      $this->drupalGet('admin/structure/views/view/test_view_broken/edit');
+
+      $href = "admin/structure/views/nojs/handler/test_view_broken/default/$type/id_broken";
+      $text = 'Broken/missing handler';
+
+      // Test that the handler edit link is present.
+      $this->assertSession()->elementsCount('xpath', "//a[contains(@href, '{$href}')]", 1);
+      $result = $this->assertSession()->elementTextEquals('xpath', "//a[contains(@href, '{$href}')]", $text);
+
+      $this->drupalGet($href);
+      $this->assertSession()->elementTextContains('xpath', '//h1', $text);
+
+      $original_configuration = [
+        'field' => 'id_broken',
+        'id' => 'id_broken',
+        'relationship' => 'none',
+        'table' => 'views_test_data',
+        'plugin_id' => 'numeric',
+      ];
+
+      foreach ($original_configuration as $key => $value) {
+        $this->assertSession()->pageTextContains($key . ': ' . $value);
+      }
+    }
+  }
+
+  /**
+   * Ensures that neither node type or node ID appears multiple times.
+   *
+   * @see \Drupal\views\EntityViewsData
+   */
+  public function testNoDuplicateFields(): void {
+    $handler_types = ['field', 'filter', 'sort', 'argument'];
+
+    foreach ($handler_types as $handler_type) {
+      $add_handler_url = 'admin/structure/views/nojs/add-handler/test_node_view/default/' . $handler_type;
+      $this->drupalGet($add_handler_url);
+
+      $this->assertNoDuplicateField('ID', 'Content');
+      $this->assertNoDuplicateField('ID', 'Content revision');
+      $this->assertNoDuplicateField('Content type', 'Content');
+      $this->assertNoDuplicateField('UUID', 'Content');
+      $this->assertNoDuplicateField('Revision ID', 'Content');
+      $this->assertNoDuplicateField('Revision ID', 'Content revision');
+    }
+  }
+
+  /**
+   * Ensures that no missing help text is shown.
+   *
+   * @see \Drupal\views\EntityViewsData
+   */
+  public function testErrorMissingHelp(): void {
+    // Test that the error message is not shown for entity fields but an empty
+    // description field is shown instead.
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_node_view/default/field');
+    $this->assertSession()->pageTextNotContains('Error: missing help');
+    $this->assertSession()->responseContains('<td class="description"></td>');
+
+    // Test that no error message is shown for other fields.
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_view_empty/default/field');
+    $this->assertSession()->pageTextNotContains('Error: missing help');
+  }
+
+  /**
+   * Asserts that fields only appear once.
+   *
+   * @param string $field_name
+   *   The field name.
+   * @param string $entity_type
+   *   The entity type to which the field belongs.
+   *
+   * @internal
+   */
+  public function assertNoDuplicateField(string $field_name, string $entity_type): void {
+    $this->assertSession()->elementsCount('xpath', '//td[.="' . $entity_type . '"]/preceding-sibling::td[@class="title" and .="' . $field_name . '"]', 1);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/NewViewConfigSchemaTest.php

@@ -0,0 +1,61 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests configuration schema against new views.
+ *
+ * @group views_ui
+ */
+class NewViewConfigSchemaTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'views_ui',
+    'node',
+    'comment',
+    'file',
+    'taxonomy',
+    'dblog',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests creating brand new views.
+   */
+  public function testNewViews(): void {
+    $this->drupalLogin($this->drupalCreateUser(['administer views']));
+
+    // Create views with all core Views wizards.
+    $wizards = [
+      // Wizard with their own classes.
+      'node',
+      'node_revision',
+      'users',
+      'comment',
+      'file_managed',
+      'taxonomy_term',
+      'watchdog',
+    ];
+    foreach ($wizards as $wizard_key) {
+      $edit = [];
+      $edit['label'] = $this->randomString();
+      $edit['id'] = $this->randomMachineName();
+      $edit['show[wizard_key]'] = $wizard_key;
+      $edit['description'] = $this->randomString();
+      $this->drupalGet('admin/structure/views/add');
+      $this->submitForm($edit, 'Save and edit');
+    }
+  }
+
+}

core/modules/views_ui/tests/src/Functional/OverrideDisplaysTest.php

@@ -0,0 +1,225 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests that displays can be correctly overridden via the user interface.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class OverrideDisplaysTest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->drupalPlaceBlock('page_title_block');
+  }
+
+  /**
+   * Tests that displays can be overridden via the UI.
+   */
+  public function testOverrideDisplays(): void {
+    // Create a basic view that shows all content, with a page and a block
+    // display.
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['page[create]'] = 1;
+    $view['page[path]'] = $this->randomMachineName(16);
+    $view['block[create]'] = 1;
+    $view_path = $view['page[path]'];
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Configure its title. Since the page and block both started off with the
+    // same (empty) title in the views wizard, we expect the wizard to have set
+    // things up so that they both inherit from the default display, and we
+    // therefore only need to change that to have it take effect for both.
+    $edit = [];
+    $edit['title'] = $original_title = $this->randomMachineName(16);
+    $edit['override[dropdown]'] = 'default';
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_1/title");
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet("admin/structure/views/view/{$view['id']}/edit/page_1");
+    $this->submitForm([], 'Save');
+
+    // Add a node that will appear in the view, so that the block will actually
+    // be displayed.
+    $this->drupalCreateContentType(['type' => 'page']);
+    $this->drupalCreateNode();
+
+    // Make sure the title appears in the page.
+    $this->drupalGet($view_path);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($original_title);
+
+    // Confirm that the view block is available in the block administration UI.
+    $this->drupalGet('admin/structure/block/list/' . $this->config('system.theme')->get('default'));
+    $this->clickLink('Place block');
+    $this->assertSession()->pageTextContains($view['label']);
+
+    // Place the block.
+    $this->container->get('plugin.manager.block')->clearCachedDefinitions();
+    $this->drupalPlaceBlock("views_block:{$view['id']}-block_1");
+
+    // Make sure the title appears in the block.
+    $this->drupalGet('');
+    $this->assertSession()->pageTextContains($original_title);
+
+    // Change the title for the page display only, and make sure that the
+    // original title still appears on the page.
+    $edit = [];
+    $edit['title'] = $new_title = $this->randomMachineName(16);
+    $edit['override[dropdown]'] = 'page_1';
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_1/title");
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet("admin/structure/views/view/{$view['id']}/edit/page_1");
+    $this->submitForm([], 'Save');
+    $this->drupalGet($view_path);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($new_title);
+    $this->assertSession()->pageTextContains($original_title);
+  }
+
+  /**
+   * Tests that the wizard correctly sets up default and overridden displays.
+   */
+  public function testWizardMixedDefaultOverriddenDisplays(): void {
+    // Create a basic view with a page, block, and feed. Give the page and feed
+    // identical titles, but give the block a different one, so we expect the
+    // page and feed to inherit their titles from the default display, but the
+    // block to override it.
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['page[create]'] = 1;
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $this->randomMachineName(16);
+    $view['page[feed]'] = 1;
+    $view['page[feed_properties][path]'] = $this->randomMachineName(16);
+    $view['block[create]'] = 1;
+    $view['block[title]'] = $this->randomMachineName(16);
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Add a node that will appear in the view, so that the block will actually
+    // be displayed.
+    $this->drupalCreateContentType(['type' => 'page']);
+    $this->drupalCreateNode();
+
+    // Make sure that the feed, page and block all start off with the correct
+    // titles.
+    $this->drupalGet($view['page[path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($view['page[title]']);
+    $this->assertSession()->pageTextNotContains($view['block[title]']);
+    $this->drupalGet($view['page[feed_properties][path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->responseContains($view['page[title]']);
+    $this->assertSession()->responseNotContains($view['block[title]']);
+
+    // Confirm that the block is available in the block administration UI.
+    $this->drupalGet('admin/structure/block/list/' . $this->config('system.theme')->get('default'));
+    $this->clickLink('Place block');
+    $this->assertSession()->pageTextContains($view['label']);
+
+    // Put the block into the first sidebar region, and make sure it will not
+    // display on the view's page display (since we will be searching for the
+    // presence/absence of the view's title in both the page and the block).
+    $this->container->get('plugin.manager.block')->clearCachedDefinitions();
+    $this->drupalPlaceBlock("views_block:{$view['id']}-block_1", [
+      'visibility' => [
+        'request_path' => [
+          'pages' => '/' . $view['page[path]'],
+          'negate' => TRUE,
+        ],
+      ],
+    ]);
+
+    $this->drupalGet('');
+    $this->assertSession()->pageTextContains($view['block[title]']);
+    $this->assertSession()->pageTextNotContains($view['page[title]']);
+
+    // Edit the page and change the title. This should automatically change
+    // the feed's title also, but not the block.
+    $edit = [];
+    $edit['title'] = $new_default_title = $this->randomMachineName(16);
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/page_1/title");
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet("admin/structure/views/view/{$view['id']}/edit/page_1");
+    $this->submitForm([], 'Save');
+    $this->drupalGet($view['page[path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($new_default_title);
+    $this->assertSession()->pageTextNotContains($view['page[title]']);
+    $this->assertSession()->pageTextNotContains($view['block[title]']);
+    $this->drupalGet($view['page[feed_properties][path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->responseContains($new_default_title);
+    $this->assertSession()->responseNotContains($view['page[title]']);
+    $this->assertSession()->responseNotContains($view['block[title]']);
+    $this->drupalGet('');
+    $this->assertSession()->pageTextNotContains($new_default_title);
+    $this->assertSession()->pageTextNotContains($view['page[title]']);
+    $this->assertSession()->pageTextContains($view['block[title]']);
+
+    // Edit the block and change the title. This should automatically change
+    // the block title only, and leave the defaults alone.
+    $edit = [];
+    $edit['title'] = $new_block_title = $this->randomMachineName(16);
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/block_1/title");
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet("admin/structure/views/view/{$view['id']}/edit/block_1");
+    $this->submitForm([], 'Save');
+    $this->drupalGet($view['page[path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains($new_default_title);
+    $this->drupalGet($view['page[feed_properties][path]']);
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->responseContains($new_default_title);
+    $this->assertSession()->responseNotContains($new_block_title);
+    $this->drupalGet('');
+    $this->assertSession()->pageTextContains($new_block_title);
+    $this->assertSession()->pageTextNotContains($view['block[title]']);
+  }
+
+  /**
+   * Tests that the revert to all displays select-option works as expected.
+   */
+  public function testRevertAllDisplays(): void {
+    // Create a basic view with a page, block.
+    // Because there is both a title on page and block we expect the title on
+    // the block be overridden.
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['page[create]'] = 1;
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $this->randomMachineName(16);
+    $view['block[create]'] = 1;
+    $view['block[title]'] = $this->randomMachineName(16);
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Revert the title of the block to the default ones, but submit some new
+    // values to be sure that the new value is not stored.
+    $edit = [];
+    $edit['title'] = $this->randomMachineName();
+    $edit['override[dropdown]'] = 'default_revert';
+
+    $this->drupalGet("admin/structure/views/nojs/display/{$view['id']}/block_1/title");
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet("admin/structure/views/view/{$view['id']}/edit/block_1");
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains($view['page[title]']);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/PreviewTest.php

@@ -0,0 +1,207 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the UI preview functionality.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class PreviewTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = [
+    'test_preview',
+    'test_preview_error',
+    'test_pager_full',
+    'test_mini_pager',
+    'test_click_sort',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests contextual links in the preview form.
+   */
+  public function testPreviewContextual(): void {
+    \Drupal::service('module_installer')->install(['contextual']);
+    $this->resetAll();
+
+    $this->drupalGet('admin/structure/views/view/test_preview/edit');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->submitForm($edit = [], 'Update preview');
+
+    // Verify that the contextual link to add a new field is shown.
+    $selector = $this->assertSession()->buildXPathQuery('//div[@id="views-live-preview"]//ul[contains(@class, :ul-class)]/li/a[contains(@href, :href)]', [
+      ':ul-class' => 'contextual-links',
+      ':href' => '/admin/structure/views/nojs/add-handler/test_preview/default/filter',
+    ]);
+    $this->assertSession()->elementsCount('xpath', $selector, 1);
+
+    $this->submitForm(['view_args' => '100'], 'Update preview');
+
+    // Test that area text and exposed filters are present and rendered.
+    $this->assertSession()->fieldExists('id');
+    $this->assertSession()->pageTextContains('Test header text');
+    $this->assertSession()->pageTextContains('Test footer text');
+    $this->assertSession()->pageTextContains('Test empty text');
+
+    $this->submitForm(['view_args' => '0'], 'Update preview');
+
+    // Test that area text and exposed filters are present and rendered.
+    $this->assertSession()->fieldExists('id');
+    $this->assertSession()->pageTextContains('Test header text');
+    $this->assertSession()->pageTextContains('Test footer text');
+    $this->assertSession()->pageTextContains('Test empty text');
+  }
+
+  /**
+   * Tests arguments in the preview form.
+   */
+  public function testPreviewUI(): void {
+    $this->drupalGet('admin/structure/views/view/test_preview/edit');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm($edit = [], 'Update preview');
+
+    $selector = '//div[@class = "views-row"]';
+    $this->assertSession()->elementsCount('xpath', $selector, 5);
+
+    // Filter just the first result.
+    $this->submitForm($edit = ['view_args' => '1'], 'Update preview');
+    $this->assertSession()->elementsCount('xpath', $selector, 1);
+
+    // Filter for no results.
+    $this->submitForm($edit = ['view_args' => '100'], 'Update preview');
+    $this->assertSession()->elementNotExists('xpath', $selector);
+
+    // Test that area text and exposed filters are present and rendered.
+    $this->assertSession()->fieldExists('id');
+    $this->assertSession()->pageTextContains('Test header text');
+    $this->assertSession()->pageTextContains('Test footer text');
+    $this->assertSession()->pageTextContains('Test empty text');
+
+    // Test feed preview.
+    $view = [];
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['page[create]'] = 1;
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $this->randomMachineName(16);
+    $view['page[feed]'] = 1;
+    $view['page[feed_properties][path]'] = $this->randomMachineName(16);
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+    $this->clickLink('Feed');
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->elementTextContains('xpath', '//div[@id="views-live-preview"]/pre', '<title>' . $view['page[title]'] . '</title>');
+
+    // Test the non-default UI display options.
+    // Statistics only, no query.
+    $settings = \Drupal::configFactory()->getEditable('views.settings');
+    $settings->set('ui.show.performance_statistics', TRUE)->save();
+    $this->drupalGet('admin/structure/views/view/test_preview/edit');
+    $this->submitForm($edit = ['view_args' => '100'], 'Update preview');
+    $this->assertSession()->pageTextContains('Query build time');
+    $this->assertSession()->pageTextContains('Query execute time');
+    $this->assertSession()->pageTextContains('View render time');
+    $this->assertSession()->responseNotContains('<strong>Query</strong>');
+
+    // Statistics and query.
+    $settings->set('ui.show.sql_query.enabled', TRUE)->save();
+    $this->submitForm($edit = ['view_args' => '100'], 'Update preview');
+    $this->assertSession()->pageTextContains('Query build time');
+    $this->assertSession()->pageTextContains('Query execute time');
+    $this->assertSession()->pageTextContains('View render time');
+    $this->assertSession()->responseContains('<strong>Query</strong>');
+    $query_string = <<<SQL
+SELECT "views_test_data"."name" AS "views_test_data_name"
+FROM
+{views_test_data} "views_test_data"
+WHERE (views_test_data.id = '100')
+SQL;
+    $this->assertSession()->assertEscaped($query_string);
+
+    // Test that the statistics and query are rendered above the preview.
+    $this->assertLessThan(strpos($this->getSession()->getPage()->getContent(), 'js-view-dom-id'), strpos($this->getSession()->getPage()->getContent(), 'views-query-info'));
+
+    // Test that statistics and query rendered below the preview.
+    $settings->set('ui.show.sql_query.where', 'below')->save();
+    $this->submitForm($edit = ['view_args' => '100'], 'Update preview');
+    $this->assertLessThan(strpos($this->getSession()->getPage()->getContent(), 'views-query-info'), strpos($this->getSession()->getPage()->getContent(), 'js-view-dom-id'), 'Statistics shown below the preview.');
+
+    // Test that the preview title isn't double escaped.
+    $this->drupalGet("admin/structure/views/nojs/display/test_preview/default/title");
+    $this->submitForm($edit = ['title' => 'Double & escaped'], 'Apply');
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->elementsCount('xpath', '//div[@id="views-live-preview"]/div[contains(@class, views-query-info)]//td[text()="Double & escaped"]', 1);
+  }
+
+  /**
+   * Tests the additional information query info area.
+   */
+  public function testPreviewAdditionalInfo(): void {
+    \Drupal::service('module_installer')->install(['views_ui_test']);
+    $this->resetAll();
+
+    $this->drupalGet('admin/structure/views/view/test_preview/edit');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm($edit = [], 'Update preview');
+
+    // Check for implementation of hook_views_preview_info_alter().
+    // @see views_ui_test.module
+    // Verify that Views Query Preview Info area was altered.
+    $this->assertSession()->elementsCount('xpath', '//div[@id="views-live-preview"]/div[contains(@class, views-query-info)]//td[text()="Test row count"]', 1);
+    // Check that additional assets are attached.
+    $this->assertStringContainsString('views_ui_test/views_ui_test.test', $this->getDrupalSettings()['ajaxPageState']['libraries'], 'Attached library found.');
+    $this->assertSession()->responseContains('css/views_ui_test.test.css');
+  }
+
+  /**
+   * Tests view validation error messages in the preview.
+   */
+  public function testPreviewError(): void {
+    $this->drupalGet('admin/structure/views/view/test_preview_error/edit');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm($edit = [], 'Update preview');
+
+    $this->assertSession()->pageTextContains('Unable to preview due to validation errors.');
+  }
+
+  /**
+   * Tests HTML is filtered from the view title when previewing.
+   */
+  public function testPreviewTitle(): void {
+    // Update the view and change title with html tags.
+    \Drupal::configFactory()->getEditable('views.view.test_preview')
+      ->set('display.default.display_options.title', '<strong>Test preview title</strong>')
+      ->save();
+
+    $this->drupalGet('admin/structure/views/view/test_preview/edit');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->pageTextContains('Test preview title');
+    // Ensure allowed HTML tags are still displayed.
+    $this->assertCount(2, $this->xpath('//div[@id="views-live-preview"]//strong[text()=:text]', [':text' => 'Test preview title']));
+
+    // Ensure other tags are filtered.
+    \Drupal::configFactory()->getEditable('views.view.test_preview')
+      ->set('display.default.display_options.title', '<b>Test preview title</b>')
+      ->save();
+    $this->submitForm([], 'Update preview');
+    $this->assertCount(0, $this->xpath('//div[@id="views-live-preview"]//b[text()=:text]', [':text' => 'Test preview title']));
+  }
+
+}

core/modules/views_ui/tests/src/Functional/QueryTest.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+use Drupal\views\Entity\View;
+
+/**
+ * Tests query plugins.
+ *
+ * @group views_ui
+ */
+class QueryTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function viewsData() {
+    $data = parent::viewsData();
+    $data['views_test_data']['table']['base']['query_id'] = 'query_test';
+
+    return $data;
+  }
+
+  /**
+   * Tests query plugins settings.
+   */
+  public function testQueryUI(): void {
+    $view = View::load('test_view');
+    $display = &$view->getDisplay('default');
+    $display['display_options']['query'] = ['type' => 'query_test'];
+    $view->save();
+
+    // Save some query settings.
+    $query_settings_path = "admin/structure/views/nojs/display/test_view/default/query";
+    $random_value = $this->randomMachineName();
+    $this->drupalGet($query_settings_path);
+    $this->submitForm(['query[options][test_setting]' => $random_value], 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Check that the settings are saved into the view itself.
+    $view = Views::getView('test_view');
+    $view->initDisplay();
+    $view->initQuery();
+    $this->assertEquals($random_value, $view->query->options['test_setting'], 'Query settings got saved');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/RearrangeFieldsTest.php

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the reordering of fields via AJAX.
+ *
+ * @group views_ui
+ * @see \Drupal\views_ui\Form\Ajax\Rearrange
+ */
+class RearrangeFieldsTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Gets the fields from the View.
+   */
+  protected function getViewFields($view_name = 'test_view', $display_id = 'default') {
+    $view = Views::getView($view_name);
+    $view->setDisplay($display_id);
+    $fields = [];
+    foreach ($view->displayHandlers->get('default')->getHandlers('field') as $field => $handler) {
+      $fields[] = $field;
+    }
+    return $fields;
+  }
+
+  /**
+   * Check if the fields are in the correct order.
+   *
+   * @param string $view_name
+   *   The name of the view.
+   * @param array $fields
+   *   Array of field names.
+   *
+   * @internal
+   */
+  protected function assertFieldOrder(string $view_name, array $fields): void {
+    $this->drupalGet('admin/structure/views/nojs/rearrange/' . $view_name . '/default/field');
+
+    foreach ($fields as $idx => $field) {
+      $this->assertSession()->fieldValueEquals('edit-fields-' . $field . '-weight', $idx + 1);
+    }
+  }
+
+  /**
+   * Tests field sorting.
+   */
+  public function testRearrangeFields(): void {
+    $view_name = 'test_view';
+
+    // Checks that the order on the rearrange form matches the creation order.
+    $this->assertFieldOrder($view_name, $this->getViewFields($view_name));
+
+    // Checks that a field is not deleted if a value is not passed back.
+    $fields = [];
+    $this->drupalGet('admin/structure/views/nojs/rearrange/' . $view_name . '/default/field');
+    $this->submitForm($fields, 'Apply');
+    $this->assertFieldOrder($view_name, $this->getViewFields($view_name));
+
+    // Checks that revers the new field order is respected.
+    $reversedFields = array_reverse($this->getViewFields($view_name));
+    $fields = [];
+    foreach ($reversedFields as $delta => $field) {
+      $fields['fields[' . $field . '][weight]'] = $delta;
+    }
+    $fields_count = count($fields);
+    $this->drupalGet('admin/structure/views/nojs/rearrange/' . $view_name . '/default/field');
+    $this->submitForm($fields, 'Apply');
+    $this->assertFieldOrder($view_name, $reversedFields);
+
+    // Checks that there is a remove link for each field.
+    $this->assertCount($fields_count, $this->cssSelect('a.views-remove-link'));
+  }
+
+}

core/modules/views_ui/tests/src/Functional/RedirectTest.php

@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the redirecting after saving a views.
+ *
+ * @group views_ui
+ */
+class RedirectTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view', 'test_redirect_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the redirecting.
+   */
+  public function testRedirect(): void {
+    $view_name = 'test_view';
+
+    $random_destination = $this->randomMachineName();
+    $edit_path = "admin/structure/views/view/$view_name/edit";
+
+    // Verify that the user gets redirected to the expected page defined in the
+    // destination.
+    $this->drupalGet($edit_path, ['query' => ['destination' => $random_destination]]);
+    $this->submitForm([], 'Save');
+    $this->assertSession()->addressEquals($random_destination);
+
+    // Setup a view with a certain page display path. If you change the path
+    // but have the old URL in the destination the user should be redirected to
+    // the new path.
+    $view_name = 'test_redirect_view';
+    $new_path = $this->randomMachineName();
+
+    $edit_path = "admin/structure/views/view/$view_name/edit";
+    $path_edit_path = "admin/structure/views/nojs/display/$view_name/page_1/path";
+
+    $this->drupalGet($path_edit_path);
+    $this->submitForm(['path' => $new_path], 'Apply');
+    $this->drupalGet($edit_path, ['query' => ['destination' => 'test-redirect-view']]);
+    $this->submitForm([], 'Save');
+    // Verify that the user gets redirected to the expected page after changing
+    // the URL of a page display.
+    $this->assertSession()->addressEquals($new_path);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ReportFieldsTest.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+
+/**
+ * Tests the Views fields report page.
+ *
+ * @group views_ui
+ */
+class ReportFieldsTest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $testViews = ['test_field_field_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['entity_test'];
+
+  /**
+   * Tests the Views fields report page.
+   */
+  public function testReportFields(): void {
+    $this->drupalGet('admin/reports/fields/views-fields');
+    $this->assertSession()->pageTextContains('Used in views');
+    $this->assertSession()->pageTextContains('No fields have been used in views yet.');
+
+    // Set up the field_test field.
+    $field_storage = FieldStorageConfig::create([
+      'field_name' => 'field_test',
+      'type' => 'integer',
+      'entity_type' => 'entity_test',
+    ]);
+    $field_storage->save();
+
+    $field = FieldConfig::create([
+      'field_name' => 'field_test',
+      'entity_type' => 'entity_test',
+      'bundle' => 'entity_test',
+    ]);
+    $field->save();
+
+    // Assert that the newly created field appears in the overview.
+    $this->drupalGet('admin/reports/fields/views-fields');
+    $this->assertSession()->responseContains('<td>field_test</td>');
+    $this->assertSession()->responseContains('>test_field_field_test</a>');
+    $this->assertSession()->pageTextContains('Used in views');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ReportTest.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests existence of the views plugin report.
+ *
+ * @group views_ui
+ */
+class ReportTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views', 'views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Stores an admin user used by the different tests.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $adminUser;
+
+  /**
+   * Tests the existence of the views plugin report.
+   */
+  public function testReport(): void {
+    $this->drupalLogin($this->adminUser);
+
+    // Test the report page.
+    $this->drupalGet('admin/reports/views-plugins');
+    $this->assertSession()->statusCodeEquals(200);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/RowUITest.php

@@ -0,0 +1,94 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Core\Entity\Entity\EntityViewMode;
+use Drupal\views\Views;
+
+/**
+ * Tests the UI of row plugins.
+ *
+ * @group views_ui
+ * @see \Drupal\views_test_data\Plugin\views\row\RowTest.
+ */
+class RowUITest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests changing the row plugin and changing some options of a row.
+   */
+  public function testRowUI(): void {
+    $view_name = 'test_view';
+    $view_edit_url = "admin/structure/views/view/$view_name/edit";
+
+    $row_plugin_url = "admin/structure/views/nojs/display/$view_name/default/row";
+    $row_options_url = "admin/structure/views/nojs/display/$view_name/default/row_options";
+
+    $this->drupalGet($row_plugin_url);
+    $this->assertSession()->fieldValueEquals('row[type]', 'fields');
+
+    $edit = [
+      'row[type]' => 'test_row',
+    ];
+    $this->submitForm($edit, 'Apply');
+    // Make sure the custom settings form from the test plugin appears.
+    $this->assertSession()->fieldExists('row_options[test_option]');
+    $random_name = $this->randomMachineName();
+    $edit = [
+      'row_options[test_option]' => $random_name,
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet($row_options_url);
+    // Make sure the custom settings form field has the expected value stored.
+    $this->assertSession()->fieldValueEquals('row_options[test_option]', $random_name);
+
+    $this->drupalGet($view_edit_url);
+    $this->submitForm([], 'Save');
+    $this->assertSession()->linkExists('Test row plugin', 0, 'Make sure the test row plugin is shown in the UI');
+
+    $view = Views::getView($view_name);
+    $view->initDisplay();
+    $row = $view->display_handler->getOption('row');
+    $this->assertEquals('test_row', $row['type'], 'Make sure that the test_row got saved as used row plugin.');
+    $this->assertEquals($random_name, $row['options']['test_option'], 'Make sure that the custom settings field got saved as expected.');
+
+    $this->drupalGet($row_plugin_url);
+    $this->submitForm(['row[type]' => 'fields'], 'Apply');
+    $this->drupalGet($row_plugin_url);
+    $this->assertSession()->statusCodeEquals(200);
+    // Make sure that 'fields' was saved as the row plugin.
+    $this->assertSession()->fieldValueEquals('row[type]', 'fields');
+
+    // Ensure that entity row plugins appear.
+    $view_name = 'content';
+    $row_plugin_url = "admin/structure/views/nojs/display/$view_name/default/row";
+    $row_options_url = "admin/structure/views/nojs/display/$view_name/default/row_options";
+
+    $this->drupalGet($row_plugin_url);
+    $this->submitForm(['row[type]' => 'entity:node'], 'Apply');
+    $this->assertSession()->addressEquals($row_options_url);
+    // Make sure the custom settings form from the entity row plugin appears.
+    $this->assertSession()->fieldValueEquals('row_options[view_mode]', 'teaser');
+
+    // Change the teaser label to have markup so we can test escaping.
+    $teaser = EntityViewMode::load('node.teaser');
+    $teaser->set('label', 'Teaser <em>markup</em>');
+    $teaser->save();
+    $this->drupalGet('admin/structure/views/view/frontpage/edit/default');
+    $this->assertSession()->assertEscaped('Teaser <em>markup</em>');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/SettingsTest.php

@@ -0,0 +1,169 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Core\Database\Database;
+
+/**
+ * Tests all ui related settings under admin/structure/views/settings.
+ *
+ * @group views_ui
+ */
+class SettingsTest extends UITestBase {
+
+  /**
+   * Stores an admin user used by the different tests.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+    $this->drupalPlaceBlock('local_tasks_block');
+  }
+
+  /**
+   * Tests the settings for the edit ui.
+   */
+  public function testEditUI(): void {
+    $this->drupalLogin($this->adminUser);
+
+    // Test the settings tab exists.
+    $this->drupalGet('admin/structure/views');
+    $this->assertSession()->linkNotExists('admin/structure/views/settings');
+
+    // Test the confirmation message.
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->pageTextContains('The configuration options have been saved.');
+
+    // Configure to always show the default display.
+    $edit = [
+      'ui_show_default_display' => TRUE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $view = [];
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['description'] = $this->randomMachineName(16);
+    $view['page[create]'] = TRUE;
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $this->randomMachineName(16);
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Configure to not always show the default display.
+    // If you have a view without a page or block the default display should be
+    // still shown.
+    $edit = [
+      'ui_show_default_display' => FALSE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $view['page[create]'] = FALSE;
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Create a view with an additional display, so default should be hidden.
+    $view['page[create]'] = TRUE;
+    $view['id'] = $this->randomMachineName();
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    $this->assertSession()->linkNotExists('Default');
+
+    // Configure to always show the advanced settings.
+    // @todo It doesn't seem to be a way to test this as this works just on js.
+
+    // Configure to show the embeddable display.
+    $edit = [
+      'ui_show_display_embed' => TRUE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $view['id'] = $this->randomMachineName();
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+    $this->assertSession()->buttonExists('edit-displays-top-add-display-embed');
+
+    $edit = [
+      'ui_show_display_embed' => FALSE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+    $this->assertSession()->buttonNotExists('edit-displays-top-add-display-embed');
+
+    // Configure to hide/show the sql at the preview.
+    $edit = [
+      'ui_show_sql_query_enabled' => FALSE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $view['id'] = $this->randomMachineName();
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Verify that the views sql is hidden.
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->elementNotExists('xpath', '//div[@class="views-query-info"]/pre');
+
+    $edit = [
+      'ui_show_sql_query_enabled' => TRUE,
+    ];
+    $this->drupalGet('admin/structure/views/settings');
+    $this->submitForm($edit, 'Save configuration');
+
+    $view['id'] = $this->randomMachineName();
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    // Verify that the views sql is shown.
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->elementExists('xpath', '//div[@class="views-query-info"]//pre');
+    // Verify that no placeholders are shown in the views sql.
+    $this->assertSession()->elementTextNotContains('xpath', '//div[@class="views-query-info"]//pre', 'db_condition_placeholder');
+    // Verify that the placeholders in the views sql are replaced by the actual
+    // values.
+    $this->assertSession()->elementTextContains('xpath', '//div[@class="views-query-info"]//pre', Database::getConnection()->escapeField("node_field_data.status") . " = '1'");
+
+    // Test the advanced settings form.
+
+    // Test the confirmation message.
+    $this->drupalGet('admin/structure/views/settings/advanced');
+    $this->submitForm([], 'Save configuration');
+    $this->assertSession()->pageTextContains('The configuration options have been saved.');
+
+    $edit = [
+      'sql_signature' => TRUE,
+    ];
+    $this->drupalGet('admin/structure/views/settings/advanced');
+    $this->submitForm($edit, 'Save configuration');
+
+    $this->assertSession()->checkboxChecked('edit-sql-signature');
+
+    // Test the "Clear Views' cache" button.
+    $this->drupalGet('admin/structure/views/settings/advanced');
+    $this->submitForm([], "Clear Views' cache");
+    $this->assertSession()->pageTextContains('The cache has been cleared.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/StorageTest.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\views\Views;
+
+/**
+ * Tests the UI of storage properties of views.
+ *
+ * @group views_ui
+ */
+class StorageTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views_ui', 'language'];
+
+  /**
+   * Tests changing label, description and tag.
+   *
+   * @see views_ui_edit_details_form
+   */
+  public function testDetails(): void {
+    $view_name = 'test_view';
+
+    ConfigurableLanguage::createFromLangcode('fr')->save();
+
+    $edit = [
+      'label' => $this->randomMachineName(),
+      'tag' => $this->randomMachineName(),
+      'description' => $this->randomMachineName(30),
+      'langcode' => 'fr',
+    ];
+
+    $this->drupalGet("admin/structure/views/nojs/edit-details/{$view_name}/default");
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+
+    $view = Views::getView($view_name);
+
+    foreach (['label', 'tag', 'description', 'langcode'] as $property) {
+      $this->assertEquals($edit[$property], $view->storage->get($property), "Make sure the property $property got probably saved.");
+    }
+  }
+
+}

core/modules/views_ui/tests/src/Functional/StyleTableTest.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the UI of views when using the table style.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\style\Table.
+ */
+class StyleTableTest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests created a table style view.
+   */
+  public function testWizard(): void {
+    // Create a new view and check that the first field has a label.
+    $view = [];
+    $view['label'] = $this->randomMachineName(16);
+    $view['id'] = $this->randomMachineName(16);
+    $view['show[wizard_key]'] = 'node';
+    $view['page[create]'] = TRUE;
+    $view['page[style][style_plugin]'] = 'table';
+    $view['page[title]'] = $this->randomMachineName(16);
+    $view['page[path]'] = $view['id'];
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    $view = Views::getView($view['id']);
+    $view->initHandlers();
+    $this->assertEquals('Title', $view->field['title']->options['label'], 'The field label for table styles is not empty.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/StyleUITest.php

@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Views;
+
+/**
+ * Tests the UI of style plugins.
+ *
+ * @group views_ui
+ * @see \Drupal\views_test_data\Plugin\views\style\StyleTest.
+ */
+class StyleUITest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests changing the style plugin and changing some options of a style.
+   */
+  public function testStyleUI(): void {
+    $view_name = 'test_view';
+    $view_edit_url = "admin/structure/views/view/$view_name/edit";
+
+    $style_plugin_url = "admin/structure/views/nojs/display/$view_name/default/style";
+    $style_options_url = "admin/structure/views/nojs/display/$view_name/default/style_options";
+
+    $this->drupalGet($style_plugin_url);
+    $this->assertSession()->fieldValueEquals('style[type]', 'default');
+
+    $edit = [
+      'style[type]' => 'test_style',
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->fieldExists('style_options[test_option]');
+    $random_name = $this->randomMachineName();
+    $edit = [
+      'style_options[test_option]' => $random_name,
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->drupalGet($style_options_url);
+    $this->assertSession()->fieldValueEquals('style_options[test_option]', $random_name);
+
+    $this->drupalGet($view_edit_url);
+    $this->submitForm([], 'Save');
+    $this->assertSession()->linkExists('Test style plugin', 0, 'Make sure the test style plugin is shown in the UI');
+
+    $view = Views::getView($view_name);
+    $view->initDisplay();
+    $style = $view->display_handler->getOption('style');
+    $this->assertEquals('test_style', $style['type'], 'Make sure that the test_style got saved as used style plugin.');
+    $this->assertEquals($random_name, $style['options']['test_option'], 'Make sure that the custom settings field got saved as expected.');
+
+    // Test that fields are working correctly in the UI for style plugins when
+    // a field row plugin is selected.
+    $this->drupalGet("admin/structure/views/view/{$view_name}/edit");
+    $this->submitForm([], 'Add Page');
+    $this->drupalGet("admin/structure/views/nojs/display/{$view_name}/page_1/row");
+    $this->submitForm(['row[type]' => 'fields'], 'Apply');
+    // If fields are being used this text will not be shown.
+    $this->assertSession()->pageTextNotContains('The selected style or row format does not use fields.');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/TokenizeAreaUITest.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\views\Entity\View;
+
+/**
+ * Tests the token display for the TokenizeAreaPluginBase UI.
+ *
+ * @see \Drupal\views\Plugin\views\area\Entity
+ * @group views_ui
+ */
+class TokenizeAreaUITest extends UITestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['entity_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests that the right tokens are shown as available for replacement.
+   */
+  public function testTokenUI(): void {
+    $entity_test = EntityTest::create(['bundle' => 'entity_test']);
+    $entity_test->save();
+
+    $default = $this->randomView([]);
+    $id = $default['id'];
+    $view = View::load($id);
+
+    $this->drupalGet($view->toUrl('edit-form'));
+
+    // Add a global NULL argument to the view for testing argument tokens.
+    $this->drupalGet("admin/structure/views/nojs/add-handler/{$id}/page_1/argument");
+    $this->submitForm(['name[views.null]' => 1], 'Add and configure contextual filters');
+    $this->submitForm([], 'Apply');
+
+    $this->drupalGet("admin/structure/views/nojs/add-handler/{$id}/page_1/header");
+    $this->submitForm(['name[views.area]' => 'views.area'], 'Add and configure header');
+    // Test that field tokens are shown.
+    $this->assertSession()->pageTextContains('{{ title }} == Content: Title');
+    // Test that argument tokens are shown.
+    $this->assertSession()->pageTextContains('{{ arguments.null }} == Global: Null title');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/TranslatedViewTest.php

@@ -0,0 +1,131 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\language\Entity\ConfigurableLanguage;
+
+// cspell:ignore fichiers
+
+/**
+ * Tests that translated strings in views UI don't override original strings.
+ *
+ * @group views_ui
+ */
+class TranslatedViewTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'config_translation',
+    'views_ui',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Languages to enable.
+   *
+   * @var array
+   */
+  protected $langcodes = [
+    'fr',
+  ];
+
+  /**
+   * Administrator user for tests.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = []): void {
+    parent::setUp($import_test_views, $modules);
+
+    $permissions = [
+      'administer site configuration',
+      'administer views',
+      'translate configuration',
+      'translate interface',
+    ];
+
+    $this->drupalPlaceBlock('local_tasks_block', ['id' => 'test_role_admin_test_local_tasks_block']);
+
+    // Create and log in user.
+    $this->adminUser = $this->drupalCreateUser($permissions);
+    $this->drupalLogin($this->adminUser);
+
+    // Add languages.
+    foreach ($this->langcodes as $langcode) {
+      ConfigurableLanguage::createFromLangcode($langcode)->save();
+    }
+    $this->resetAll();
+    $this->rebuildContainer();
+  }
+
+  public function testTranslatedStrings(): void {
+    $translation_url = 'admin/structure/views/view/files/translate/fr/add';
+    $edit_url = 'admin/structure/views/view/files';
+
+    // Check the original string.
+    $this->drupalGet($edit_url);
+    $this->assertSession()->titleEquals('Files (File) | Drupal');
+
+    // Translate the label of the view.
+    $this->drupalGet($translation_url);
+    $edit = [
+      'translation[config_names][views.view.files][label]' => 'Fichiers',
+    ];
+    $this->submitForm($edit, 'Save translation');
+
+    // Check if the label is translated.
+    $this->drupalGet($edit_url, ['language' => \Drupal::languageManager()->getLanguage('fr')]);
+    $this->assertSession()->titleEquals('Files (File) | Drupal');
+    $this->assertSession()->pageTextNotContains('Fichiers');
+
+    // Ensure that "Link URL" and "Link Path" fields are translatable.
+    // First, Add the block display and change pager's 'link display' to
+    // custom URL.
+    // Second, change filename to use plain text and rewrite output with link.
+    $this->drupalGet($edit_url);
+    $this->submitForm([], 'Add Block');
+    $this->drupalGet('admin/structure/views/nojs/display/files/block_1/link_display');
+    $edit = [
+      'link_display' => 'custom_url',
+      'link_url' => '/node',
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+    $this->drupalGet('admin/structure/views/nojs/handler/files/block_1/field/filename');
+    $edit = [
+      'override[dropdown]' => 'block_1',
+      'options[type]' => 'string',
+      'options[alter][path]' => '/node',
+      'options[alter][make_link]' => 1,
+    ];
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+
+    // Visit the translation page and ensure that field exists.
+    $this->drupalGet($translation_url);
+    $this->assertSession()->fieldExists('translation[config_names][views.view.files][display][block_1][display_options][fields][filename][alter][path]');
+    $this->assertSession()->fieldExists('translation[config_names][views.view.files][display][default][display_options][link_url]');
+
+    // Assert that the View translation link is shown when viewing a display.
+    $this->drupalGet($edit_url);
+    $this->assertSession()->linkExists('Translate view');
+    $this->drupalGet('/admin/structure/views/view/files/edit/block_1');
+    $this->assertSession()->linkExists('Translate view');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/UITestBase.php

@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Tests\views\Functional\ViewTestBase;
+
+/**
+ * Provides a base class for testing the Views UI.
+ */
+abstract class UITestBase extends ViewTestBase {
+
+  /**
+   * An admin user with the 'administer views' permission.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * An admin user with administrative permissions for views, blocks, and nodes.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $fullAdminUser;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['node', 'views_ui', 'block', 'taxonomy'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->enableViewsTestModule();
+
+    $this->adminUser = $this->drupalCreateUser(['administer views']);
+
+    $this->fullAdminUser = $this->drupalCreateUser(['administer views',
+      'administer blocks',
+      'bypass node access',
+      'access user profiles',
+      'view all revisions',
+      'administer permissions',
+    ]);
+    $this->drupalLogin($this->fullAdminUser);
+  }
+
+  /**
+   * A helper method which creates a random view.
+   */
+  public function randomView(array $view = []) {
+    // Create a new view in the UI.
+    $default = [];
+    $default['label'] = $this->randomMachineName(16);
+    $default['id'] = $this->randomMachineName(16);
+    $default['description'] = $this->randomMachineName(16);
+    $default['page[create]'] = TRUE;
+    $default['page[path]'] = $default['id'];
+
+    $view += $default;
+
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    return $default;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function drupalGet($path, array $options = [], array $headers = []) {
+    $url = $this->buildUrl($path, $options);
+
+    // Ensure that each nojs page is accessible via ajax as well.
+    if (str_contains($url, '/nojs/')) {
+      $url = preg_replace('|/nojs/|', '/ajax/', $url, 1);
+      $result = $this->drupalGet($url, $options);
+      $this->assertSession()->statusCodeEquals(200);
+      $this->assertSession()->responseHeaderEquals('Content-Type', 'application/json');
+      $this->assertNotEmpty(json_decode($result), 'Ensure that the AJAX request returned valid content.');
+    }
+
+    return parent::drupalGet($path, $options, $headers);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/UnsavedPreviewTest.php

@@ -0,0 +1,84 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests covering Preview of unsaved Views.
+ *
+ * @group views_ui
+ */
+class UnsavedPreviewTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['content'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * An admin user with the 'administer views' permission.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['node', 'views_ui'];
+
+  /**
+   * Sets up a Drupal site for running functional and integration tests.
+   */
+  protected function setUp($import_test_views = TRUE, $modules = ['views_test_config']): void {
+    parent::setUp(FALSE, $modules);
+
+    $this->adminUser = $this->drupalCreateUser(['administer views']);
+    $this->drupalLogin($this->adminUser);
+  }
+
+  /**
+   * Tests previews of unsaved new page displays.
+   */
+  public function testUnsavedPageDisplayPreview(): void {
+    $this->drupalCreateContentType(['type' => 'page']);
+    for ($i = 0; $i < 5; $i++) {
+      $this->drupalCreateNode();
+    }
+
+    $this->drupalGet('admin/structure/views/view/content');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm([], 'Add Page');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->drupalGet('admin/structure/views/nojs/display/content/page_2/path');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm(['path' => 'foobar'], 'Apply');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('This display has no path');
+
+    $this->drupalGet('admin/structure/views/view/content/edit/page_2');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm([], 'Save');
+    $this->assertSession()->statusCodeEquals(200);
+
+    $this->submitForm([], 'Update preview');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->linkByHrefExists('foobar');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ViewEditTest.php

@@ -0,0 +1,276 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Core\Database\Database;
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\views\Entity\View;
+
+/**
+ * Tests some general functionality of editing views, like deleting a view.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class ViewEditTest extends UITestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view', 'test_display', 'test_groupwise_term_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests the delete link on a views UI.
+   */
+  public function testDeleteLink(): void {
+    $this->drupalGet('admin/structure/views/view/test_view');
+    $this->assertSession()->linkExists('Delete view', 0, 'Ensure that the view delete link appears');
+
+    $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_view');
+    $this->assertInstanceOf(View::class, $view);
+    $this->clickLink('Delete view');
+    $this->assertSession()->addressEquals('admin/structure/views/view/test_view/delete');
+    $this->submitForm([], 'Delete');
+    $this->assertSession()->pageTextContains("The view {$view->label()} has been deleted.");
+
+    $this->assertSession()->addressEquals('admin/structure/views');
+    $view = $this->container->get('entity_type.manager')->getStorage('view')->load('test_view');
+    $this->assertNotInstanceOf(View::class, $view);
+  }
+
+  /**
+   * Tests the machine name and administrative comment forms.
+   */
+  public function testOtherOptions(): void {
+    \Drupal::service('module_installer')->install(['dblog']);
+    $this->drupalGet('admin/structure/views/view/test_view');
+    // Add a new attachment display.
+    $this->submitForm([], 'Add Attachment');
+    // Test that a long administrative comment is truncated.
+    $edit = ['display_comment' => 'one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen'];
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/attachment_1/display_comment');
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('one two three four five six seven eight nine ten eleven twelve thirteen…');
+
+    // Change the machine name for the display from page_1 to test_1.
+    $edit = ['display_id' => 'test_1'];
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/attachment_1/display_id');
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->linkExists('test_1');
+
+    // Save the view, and test the new ID has been saved.
+    $this->submitForm([], 'Save');
+    $view = \Drupal::entityTypeManager()->getStorage('view')->load('test_view');
+    $displays = $view->get('display');
+    $this->assertNotEmpty($displays['test_1'], 'Display data found for new display ID key.');
+    $this->assertSame('test_1', $displays['test_1']['id'], 'New display ID matches the display ID key.');
+    $this->assertArrayNotHasKey('attachment_1', $displays);
+
+    // Set to the same machine name and save the View.
+    $edit = ['display_id' => 'test_1'];
+    $this->drupalGet('admin/structure/views/nojs/display/test_view/test_1/display_id');
+    $this->submitForm($edit, 'Apply');
+    $this->submitForm([], 'Save');
+    $this->assertSession()->linkExists('test_1');
+
+    // Test the form validation with invalid IDs.
+    $machine_name_edit_url = 'admin/structure/views/nojs/display/test_view/test_1/display_id';
+    $error_text = 'Display machine name must contain only lowercase letters, numbers, or underscores.';
+
+    // Test that potential invalid display ID requests are detected
+    $this->drupalGet('admin/structure/views/ajax/handler/test_view/fake_display_name/filter/title');
+    $arguments = [
+      '@display_id' => 'fake_display_name',
+    ];
+    $logged = Database::getConnection()->select('watchdog')
+      ->fields('watchdog', ['variables'])
+      ->condition('type', 'views')
+      ->condition('message', 'setDisplay() called with invalid display ID "@display_id".')
+      ->execute()
+      ->fetchField();
+    $this->assertEquals(serialize($arguments), $logged);
+
+    $edit = ['display_id' => 'test 1'];
+    $this->drupalGet($machine_name_edit_url);
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains($error_text);
+
+    $edit = ['display_id' => 'test_1#'];
+    $this->drupalGet($machine_name_edit_url);
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains($error_text);
+
+    // Test using an existing display ID.
+    $edit = ['display_id' => 'default'];
+    $this->drupalGet($machine_name_edit_url);
+    $this->submitForm($edit, 'Apply');
+    $this->assertSession()->pageTextContains('Display id should be unique.');
+
+    // Test that the display ID has not been changed.
+    $this->drupalGet('admin/structure/views/view/test_view/edit/test_1');
+    $this->assertSession()->linkExists('test_1');
+
+    // Test that validation does not run on cancel.
+    $this->drupalGet('admin/structure/views/view/test_view');
+    // Delete the field to cause an error on save.
+    $fields = [];
+    $fields['fields[age][removed]'] = 1;
+    $fields['fields[id][removed]'] = 1;
+    $fields['fields[name][removed]'] = 1;
+    $this->drupalGet('admin/structure/views/nojs/rearrange/test_view/default/field');
+    $this->submitForm($fields, 'Apply');
+    $this->submitForm([], 'Save');
+    $this->submitForm([], 'Cancel');
+    // Verify that no error message is displayed.
+    $this->assertSession()->elementNotExists('xpath', '//div[contains(@class, "error")]');
+    // Verify page was redirected to the view listing.
+    $this->assertSession()->addressEquals('admin/structure/views');
+  }
+
+  /**
+   * Tests the language options on the views edit form.
+   */
+  public function testEditFormLanguageOptions(): void {
+    $assert_session = $this->assertSession();
+
+    // Language options should not exist without language module.
+    $test_views = [
+      'test_view' => 'default',
+      'test_display' => 'page_1',
+    ];
+    foreach ($test_views as $view_name => $display) {
+      $this->drupalGet('admin/structure/views/view/' . $view_name);
+      $this->assertSession()->statusCodeEquals(200);
+      $langcode_url = 'admin/structure/views/nojs/display/' . $view_name . '/' . $display . '/rendering_language';
+      $this->assertSession()->linkByHrefNotExists($langcode_url);
+      $assert_session->linkNotExistsExact('Content language selected for page');
+      $this->assertSession()->linkNotExists('Content language of view row');
+    }
+
+    // Make the site multilingual and test the options again.
+    $this->container->get('module_installer')->install(['language', 'content_translation']);
+    ConfigurableLanguage::createFromLangcode('hu')->save();
+    $this->resetAll();
+    $this->rebuildContainer();
+
+    // Language options should now exist with entity language the default.
+    foreach ($test_views as $view_name => $display) {
+      $this->drupalGet('admin/structure/views/view/' . $view_name);
+      $this->assertSession()->statusCodeEquals(200);
+      $langcode_url = 'admin/structure/views/nojs/display/' . $view_name . '/' . $display . '/rendering_language';
+      if ($view_name == 'test_view') {
+        $this->assertSession()->linkByHrefNotExists($langcode_url);
+        $assert_session->linkNotExistsExact('Content language selected for page');
+        $this->assertSession()->linkNotExists('Content language of view row');
+      }
+      else {
+        $this->assertSession()->linkByHrefExists($langcode_url);
+        $assert_session->linkNotExistsExact('Content language selected for page');
+        $this->assertSession()->linkExists('Content language of view row');
+      }
+
+      $this->drupalGet($langcode_url);
+      $this->assertSession()->statusCodeEquals(200);
+      if ($view_name == 'test_view') {
+        $this->assertSession()->pageTextContains('The view is not based on a translatable entity type or the site is not multilingual.');
+      }
+      else {
+        $this->assertSession()->fieldValueEquals('rendering_language', '***LANGUAGE_entity_translation***');
+        // Test that the order of the language list is similar to other language
+        // lists, such as in the content translation settings.
+        $expected_elements = [
+          '***LANGUAGE_entity_translation***',
+          '***LANGUAGE_entity_default***',
+          '***LANGUAGE_site_default***',
+          '***LANGUAGE_language_interface***',
+          'en',
+          'hu',
+        ];
+        $elements = $this->assertSession()->selectExists('edit-rendering-language')->findAll('css', 'option');
+        $elements = array_map(function ($element) {
+          return $element->getValue();
+        }, $elements);
+        $this->assertSame($expected_elements, $elements);
+
+        // Check that the selected values are respected even we they are not
+        // supposed to be listed.
+        // Give permission to edit languages to authenticated users.
+        $edit = [
+          'authenticated[administer languages]' => TRUE,
+        ];
+        $this->drupalGet('/admin/people/permissions');
+        $this->submitForm($edit, 'Save permissions');
+        // Enable Content language negotiation so we have one more item
+        // to select.
+        $edit = [
+          'language_content[configurable]' => TRUE,
+        ];
+        $this->drupalGet('admin/config/regional/language/detection');
+        $this->submitForm($edit, 'Save settings');
+
+        // Choose the new negotiation as the rendering language.
+        $edit = [
+          'rendering_language' => '***LANGUAGE_language_content***',
+        ];
+        $this->drupalGet('/admin/structure/views/nojs/display/' . $view_name . '/' . $display . '/rendering_language');
+        $this->submitForm($edit, 'Apply');
+
+        // Disable language content negotiation.
+        $edit = [
+          'language_content[configurable]' => FALSE,
+        ];
+        $this->drupalGet('admin/config/regional/language/detection');
+        $this->submitForm($edit, 'Save settings');
+
+        // Check that the previous selection is listed and selected.
+        $this->drupalGet($langcode_url);
+        $this->assertTrue($this->assertSession()->optionExists('edit-rendering-language', '***LANGUAGE_language_content***')->isSelected());
+
+        // Check the order for the langcode filter.
+        $langcode_url = 'admin/structure/views/nojs/handler/' . $view_name . '/' . $display . '/filter/langcode';
+        $this->drupalGet($langcode_url);
+        $this->assertSession()->statusCodeEquals(200);
+
+        $expected_elements = [
+          'all',
+          '***LANGUAGE_site_default***',
+          '***LANGUAGE_language_interface***',
+          '***LANGUAGE_language_content***',
+          'en',
+          'hu',
+          'und',
+          'zxx',
+        ];
+        $elements = $this->xpath('//div[@id="edit-options-value"]//input');
+        // Compare values inside the option elements with expected values.
+        for ($i = 0; $i < count($elements); $i++) {
+          $this->assertEquals($expected_elements[$i], $elements[$i]->getAttribute('value'));
+        }
+      }
+    }
+  }
+
+  /**
+   * Tests Representative Node for a Taxonomy Term.
+   */
+  public function testRelationRepresentativeNode(): void {
+    // Populate and submit the form.
+    $edit["name[taxonomy_term_field_data.tid_representative]"] = TRUE;
+    $this->drupalGet('admin/structure/views/nojs/add-handler/test_groupwise_term_ui/default/relationship');
+    $this->submitForm($edit, 'Add and configure relationships');
+    // Apply changes.
+    $edit = [];
+    $this->drupalGet('admin/structure/views/nojs/handler/test_groupwise_term_ui/default/relationship/tid_representative');
+    $this->submitForm($edit, 'Apply');
+  }
+
+}

core/modules/views_ui/tests/src/Functional/ViewsListTest.php

@@ -0,0 +1,82 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\views\Entity\View;
+use Drupal\views\Views;
+
+/**
+ * Tests the views list.
+ *
+ * @group views_ui
+ */
+class ViewsListTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['block', 'views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * A user with permission to administer views.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE, $modules = []): void {
+    parent::setUp($import_test_views, $modules);
+
+    $this->drupalPlaceBlock('local_tasks_block');
+    $this->drupalPlaceBlock('local_actions_block');
+    $this->adminUser = $this->drupalCreateUser(['administer views']);
+    $this->drupalLogin($this->adminUser);
+  }
+
+  /**
+   * Tests that the views list does not use a pager.
+   */
+  public function testViewsListLimit(): void {
+    // Check if we can access the main views admin page.
+    $this->drupalGet('admin/structure/views');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->linkExists('Add view');
+
+    // Check that there is a link to the content view without a destination
+    // parameter.
+    $this->drupalGet('admin/structure/views');
+    $links = $this->getSession()->getPage()->findAll('xpath', "//a[contains(@href, 'admin/structure/views/view/content')]");
+    $this->assertStringEndsWith('admin/structure/views/view/content', $links[0]->getAttribute('href'));
+    $this->assertSession()->linkByHrefExists('admin/structure/views/view/content/delete?destination');
+
+    // Count default views to be subtracted from the limit.
+    $views = count(Views::getEnabledViews());
+
+    // Create multiples views.
+    $limit = 51;
+    $values = $this->config('views.view.test_view_storage')->get();
+    for ($i = 1; $i <= $limit - $views; $i++) {
+      $values['id'] = $values['label'] = 'test_view_storage_new' . $i;
+      unset($values['uuid']);
+      $created = View::create($values);
+      $created->save();
+    }
+    $this->drupalGet('admin/structure/views');
+
+    // Check that all the rows are listed.
+    $this->assertSession()->elementsCount('xpath', '//tbody/tr[contains(@class,"views-ui-list-enabled")]', $limit);
+  }
+
+}

core/modules/views_ui/tests/src/Functional/WizardTest.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Tests\views\Functional\Wizard\WizardTestBase;
+
+/**
+ * Tests the wizard.
+ *
+ * @group views_ui
+ * @see \Drupal\views\Plugin\views\display\DisplayPluginBase
+ * @see \Drupal\views\Plugin\views\display\PathPluginBase
+ * @see \Drupal\views\Plugin\views\wizard\WizardPluginBase
+ */
+class WizardTest extends WizardTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests filling in the wizard with really long strings.
+   */
+  public function testWizardFieldLength(): void {
+    $view = [];
+    $view['label'] = $this->randomMachineName(256);
+    $view['id'] = $this->randomMachineName(129);
+    $view['page[create]'] = TRUE;
+    $view['page[path]'] = $this->randomMachineName(255);
+    $view['page[title]'] = $this->randomMachineName(256);
+    $view['page[feed]'] = TRUE;
+    $view['page[feed_properties][path]'] = $this->randomMachineName(255);
+    $view['block[create]'] = TRUE;
+    $view['block[title]'] = $this->randomMachineName(256);
+    $view['rest_export[create]'] = TRUE;
+    $view['rest_export[path]'] = $this->randomMachineName(255);
+
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+
+    $this->assertSession()->pageTextContains('Machine-readable name cannot be longer than 128 characters but is currently 129 characters long.');
+    $this->assertSession()->pageTextContains('Path cannot be longer than 254 characters but is currently 255 characters long.');
+    $this->assertSession()->pageTextContains('Page title cannot be longer than 255 characters but is currently 256 characters long.');
+    $this->assertSession()->pageTextContains('View name cannot be longer than 255 characters but is currently 256 characters long.');
+    $this->assertSession()->pageTextContains('Feed path cannot be longer than 254 characters but is currently 255 characters long.');
+    $this->assertSession()->pageTextContains('Block title cannot be longer than 255 characters but is currently 256 characters long.');
+    $this->assertSession()->pageTextContains('REST export path cannot be longer than 254 characters but is currently 255 characters long.');
+
+    $view['label'] = $this->randomMachineName(255);
+    $view['id'] = $this->randomMachineName(128);
+    $view['page[create]'] = TRUE;
+    $view['page[path]'] = $this->randomMachineName(254);
+    $view['page[title]'] = $this->randomMachineName(255);
+    $view['page[feed]'] = TRUE;
+    $view['page[feed_properties][path]'] = $this->randomMachineName(254);
+    $view['block[create]'] = TRUE;
+    $view['block[title]'] = $this->randomMachineName(255);
+    $view['rest_export[create]'] = TRUE;
+    $view['rest_export[path]'] = $this->randomMachineName(254);
+
+    // Make sure the view saving was successful and the browser got redirected
+    // to the edit page.
+    $this->drupalGet('admin/structure/views/add');
+    $this->submitForm($view, 'Save and edit');
+    $this->assertSession()->addressEquals('admin/structure/views/view/' . $view['id']);
+    // Assert that the page title is correctly truncated.
+    $this->assertSession()->pageTextContains(Unicode::truncate($view['page[title]'], 32, FALSE, TRUE));
+  }
+
+}

core/modules/views_ui/tests/src/Functional/XssTest.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Functional;
+
+/**
+ * Tests the Xss vulnerability.
+ *
+ * @group views_ui
+ */
+class XssTest extends UITestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['node', 'user', 'views_ui', 'views_ui_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  public function testViewsUi(): void {
+    $this->drupalGet('admin/structure/views/view/sa_contrib_2013_035');
+    // Verify that the field admin label is properly escaped.
+    $this->assertSession()->assertEscaped('<marquee>test</marquee>');
+
+    $this->drupalGet('admin/structure/views/nojs/handler/sa_contrib_2013_035/page_1/header/area');
+    // Verify that the token label is properly escaped.
+    $this->assertSession()->assertEscaped('{{ title }} == <marquee>test</marquee>');
+    $this->assertSession()->assertEscaped('{{ title_1 }} == <script>alert("XSS")</script>');
+  }
+
+  /**
+   * Checks the admin UI for double escaping.
+   */
+  public function testNoDoubleEscaping(): void {
+    $this->drupalGet('admin/structure/views');
+    $this->assertSession()->assertNoEscaped('&lt;');
+
+    $this->drupalGet('admin/structure/views/view/sa_contrib_2013_035');
+    $this->assertSession()->assertNoEscaped('&lt;');
+
+    $this->drupalGet('admin/structure/views/nojs/handler/sa_contrib_2013_035/page_1/header/area');
+    $this->assertSession()->assertNoEscaped('&lt;');
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/AdminAjaxTest.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Tests the admin UI AJAX interactions.
+ *
+ * @group views_ui
+ */
+class AdminAjaxTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'views_ui',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'views_ui_test_theme';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->drupalLogin($this->createUser([
+      'administer views',
+    ]));
+  }
+
+  /**
+   * Confirms that form_alter is triggered after AJAX rebuilds.
+   */
+  public function testAjaxRebuild(): void {
+    \Drupal::service('theme_installer')->install(['views_ui_test_theme']);
+
+    $this->config('system.theme')
+      ->set('default', 'views_ui_test_theme')
+      ->save();
+
+    $page = $this->getSession()->getPage();
+    $assert_session = $this->assertSession();
+
+    $this->drupalGet('admin/structure/views/view/user_admin_people');
+    $assert_session->pageTextContains('This is text added to the display tabs at the top');
+    $assert_session->pageTextContains('This is text added to the display edit form');
+    $page->clickLink('User: Name (Username)');
+    $assert_session->waitForElementVisible('css', '.views-ui-dialog');
+    $page->fillField('Label', 'New Title');
+    $page->find('css', '.ui-dialog-buttonset button:contains("Apply")')->press();
+    $assert_session->waitForElementRemoved('css', '.views-ui-dialog');
+    $assert_session->pageTextContains('This is text added to the display tabs at the top');
+    $assert_session->pageTextContains('This is text added to the display edit form');
+  }
+
+  /**
+   * Tests body scroll.
+   */
+  public function testBodyScroll(): void {
+    $this->drupalGet('admin/structure/views/view/user_admin_people');
+    $page = $this->getSession()->getPage();
+    foreach (['name[views.nothing]', 'name[views.dropbutton]'] as $field) {
+      $page->find('css', '#views-add-field')->click();
+      $this->assertSession()->assertWaitOnAjaxRequest();
+      $page->checkField($field);
+      $page->find('css', '.ui-dialog-buttonset')->pressButton('Add and configure fields');
+      $this->assertSession()->assertWaitOnAjaxRequest();
+      $this->assertJsCondition('document.documentElement.style.overflow === "hidden"');
+      $page->find('css', '.ui-dialog-buttonset')->pressButton('Apply');
+      $this->assertSession()->assertWaitOnAjaxRequest();
+
+      // Check overflow.
+      $this->assertJsCondition('document.documentElement.style.overflow !== "hidden"');
+    }
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/DisplayTest.php

@@ -0,0 +1,210 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\locale\SourceString;
+use Drupal\views\Entity\View;
+use Drupal\views\Tests\ViewTestData;
+use Drupal\Tests\node\Traits\NodeCreationTrait;
+
+// cSpell:ignore Blokk hozzáadása
+
+/**
+ * Tests the display UI.
+ *
+ * @group views_ui
+ */
+class DisplayTest extends WebDriverTestBase {
+
+  use NodeCreationTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'block',
+    'contextual',
+    'node',
+    'language',
+    'locale',
+    'views',
+    'views_ui',
+    'views_test_config',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  public static $testViews = ['test_content_ajax', 'test_display'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    ViewTestData::createTestViews(self::class, ['views_test_config']);
+
+    $admin_user = $this->drupalCreateUser([
+      'administer site configuration',
+      'administer views',
+      'administer nodes',
+      'access content overview',
+      'access contextual links',
+    ]);
+
+    // Disable automatic live preview to make the sequence of calls clearer.
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.always_live_preview', FALSE)->save();
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests adding a display.
+   */
+  public function testAddDisplay(): void {
+    $this->drupalGet('admin/structure/views/view/test_content_ajax');
+    $page = $this->getSession()->getPage();
+
+    $page->find('css', '#views-display-menu-tabs .add')->click();
+
+    // Wait for the animation to complete.
+    $this->getSession()->wait(1000, "jQuery(':animated').length === 0;");
+
+    // Add the display.
+    $page->find('css', '#edit-displays-top-add-display-block')->click();
+
+    $element = $page->findById('views-display-menu-tabs')->findLink('Block');
+    $this->assertNotEmpty($element);
+  }
+
+  /**
+   * Tests setting the administrative title.
+   */
+  public function testRenameDisplayAdminName(): void {
+    $titles = ['New admin title', '</title><script>alert("alert!")</script>'];
+    foreach ($titles as $new_title) {
+      $this->drupalGet('admin/structure/views/view/test_content_ajax');
+      $page = $this->getSession()->getPage();
+
+      $page->findLink('Edit view name/description')->click();
+      $this->getSession()->executeScript("document.title = 'Initial title | " . \Drupal::config('system.site')->get('name') . "'");
+
+      $admin_name_field = $this->assertSession()
+        ->waitForField('Administrative name');
+      $dialog_buttons = $page->find('css', '.ui-dialog-buttonset');
+      $admin_name_field->setValue($new_title);
+
+      $dialog_buttons->pressButton('Apply');
+      $this->assertJsCondition("document.title === '" . $new_title . " (Content) | " . \Drupal::config('system.site')->get('name') . "'");
+    }
+  }
+
+  /**
+   * Tests contextual links on Views page displays.
+   */
+  public function testPageContextualLinks(): void {
+    $view = View::load('test_display');
+    $view->enable()->save();
+    $this->container->get('router.builder')->rebuildIfNeeded();
+
+    // Create node so the view has content and the contextual area is higher
+    // than 0 pixels.
+    $this->drupalCreateContentType(['type' => 'page']);
+    $this->createNode();
+
+    // When no "main content" block is placed, we find a contextual link
+    // placeholder for editing just the view.
+    $this->drupalGet('test-display');
+    $page = $this->getSession()->getPage();
+    $this->assertSession()->assertWaitOnAjaxRequest();
+
+    $selector = '.views-element-container';
+    $this->toggleContextualTriggerVisibility($selector);
+
+    $element = $this->getSession()->getPage()->find('css', $selector);
+    $element->find('css', '.contextual button')->press();
+
+    $contextual_container_id = 'entity.view.edit_form:view=test_display:location=page&name=test_display&display_id=page_1&langcode=en';
+    $contextual_container = $page->find('css', '[data-contextual-id="' . $contextual_container_id . '"]');
+    $this->assertNotEmpty($contextual_container);
+
+    $edit_link = $contextual_container->findLink('Edit view');
+    $this->assertNotEmpty($edit_link);
+
+    // When a "main content" is placed, we still find a contextual link
+    // placeholder for editing just the view (not the main content block).
+    // @see system_block_view_system_main_block_alter()
+    $this->drupalPlaceBlock('system_main_block', ['id' => 'main_content']);
+    $contextual_container = $page->find('css', '[data-contextual-id="' . $contextual_container_id . '"]');
+    $this->assertNotEmpty($contextual_container);
+  }
+
+  /**
+   * Toggles the visibility of a contextual trigger.
+   *
+   * @param string $selector
+   *   The selector for the element that contains the contextual Rink.
+   */
+  protected function toggleContextualTriggerVisibility($selector) {
+    // Hovering over the element itself with should be enough, but does not
+    // work. Manually remove the visually-hidden class.
+    $this->getSession()->executeScript("jQuery('{$selector} .contextual .trigger').toggleClass('visually-hidden');");
+  }
+
+  /**
+   * Test if 'add' translations are filtered from multilingual display options.
+   */
+  public function testAddDisplayBlockTranslation(): void {
+
+    // Set up an additional language (Hungarian).
+    $langcode = 'hu';
+    ConfigurableLanguage::createFromLangcode($langcode)->save();
+    $config = $this->config('language.negotiation');
+    $config->set('url.prefixes', [$langcode => $langcode])->save();
+    \Drupal::service('kernel')->rebuildContainer();
+    \Drupal::languageManager()->reset();
+
+    // Add Hungarian translations.
+    $this->addTranslation($langcode, 'Block', 'Blokk');
+    $this->addTranslation($langcode, 'Add @display', '@display hozzáadása');
+
+    $this->drupalGet('hu/admin/structure/views/view/test_display');
+    $page = $this->getSession()->getPage();
+
+    $page->find('css', '#views-display-menu-tabs .add')->click();
+
+    // Wait for the animation to complete.
+    $this->getSession()->wait(1000, "jQuery(':animated').length === 0;");
+
+    // Look for the input element, always in second spot.
+    $elements = $page->findAll('css', '.add ul input');
+    $this->assertEquals('Blokk', $elements[1]->getAttribute('value'));
+  }
+
+  /**
+   * Helper function for adding interface text translations.
+   */
+  private function addTranslation($langcode, $source_string, $translation_string) {
+    $storage = \Drupal::service('locale.storage');
+    $string = $storage->findString(['source' => $source_string]);
+    if (is_null($string)) {
+      $string = new SourceString();
+      $string
+        ->setString($source_string)
+        ->setStorage($storage)
+        ->save();
+    }
+    $storage->createTranslation([
+      'lid' => $string->getId(),
+      'language' => $langcode,
+      'translation' => $translation_string,
+    ])->save();
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/FieldDialogsTest.php

@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+use Drupal\views\Tests\ViewTestData;
+
+/**
+ * Tests the fields dialogs.
+ *
+ * @group views_ui
+ */
+class FieldDialogsTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'views',
+    'views_ui',
+    'views_test_config',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Views used by this test.
+   *
+   * @var string[]
+   */
+  public static $testViews = ['test_content_ajax'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    ViewTestData::createTestViews(self::class, ['views_test_config']);
+
+    $admin_user = $this->drupalCreateUser([
+      'administer site configuration',
+      'administer views',
+      'access content overview',
+    ]);
+
+    // Disable automatic live preview to make the sequence of calls clearer.
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.always_live_preview', FALSE)->save();
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests removing a field through the rearrange dialog.
+   */
+  public function testRemoveFieldHandler(): void {
+    $this->drupalGet('admin/structure/views/view/test_content_ajax');
+    $page = $this->getSession()->getPage();
+
+    $this->openFieldDialog();
+    $remove_link = $page->findAll('css', '.views-remove-link')[1];
+    $parent = $remove_link->getParent();
+    $this->assertTrue($remove_link->isVisible());
+    $remove_checkbox = $this->assertSession()->fieldExists('fields[title][removed]', $parent);
+    $this->assertFalse($remove_checkbox->isVisible());
+    $this->assertFalse($remove_checkbox->isChecked());
+    $remove_link->click();
+    $this->assertFalse($remove_link->isVisible());
+    $this->assertTrue($remove_checkbox->isChecked());
+  }
+
+  /**
+   * Uses the 'And/Or Rearrange' link for fields to open a dialog.
+   */
+  protected function openFieldDialog() {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+    $dropbutton = $page->find('css', '.views-ui-display-tab-bucket.field .dropbutton-toggle button');
+    $dropbutton->click();
+    $add_link = $page->findById('views-rearrange-field');
+    $this->assertTrue($add_link->isVisible(), 'And/Or Rearrange button found.');
+    $add_link->click();
+    $assert_session->assertWaitOnAjaxRequest();
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/FilterCriteriaTest.php

@@ -0,0 +1,192 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Tests the View UI filter criteria group dialog.
+ *
+ * @group views_ui
+ */
+class FilterCriteriaTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['node', 'views', 'views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $admin_user = $this->drupalCreateUser([
+      'administer site configuration',
+      'administer views',
+      'administer nodes',
+      'access content overview',
+    ]);
+
+    // Disable automatic live preview to make the sequence of calls clearer.
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.always_live_preview', FALSE)->save();
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests dialog for filter criteria.
+   */
+  public function testFilterCriteriaDialog(): void {
+    // Checks that the admin summary is not double escaped.
+    $this->drupalGet('admin/structure/views/view/who_s_online');
+    $page = $this->getSession()->getPage();
+    $this->assertNotNull($page->findLink('User: Last access (>= -15 minutes)'));
+
+    $this->drupalGet('admin/structure/views/view/content_recent');
+    $assert_session = $this->assertSession();
+    $session = $this->getSession();
+    $page = $session->getPage();
+
+    $this->openFilterDialog();
+
+    // Add a new filter group.
+    $create_new_filter_group = $page->findById('views-add-group-link');
+    $this->assertTrue($create_new_filter_group->isVisible(), 'Add group link found.');
+    $create_new_filter_group->click();
+    $assert_session->assertWaitOnAjaxRequest();
+
+    // Assert the existence of the new filter group by checking the remove group
+    // link.
+    $remove_link = $page->findLink('Remove group');
+    $this->assertTrue($remove_link->isVisible(), 'New group found.');
+
+    // Remove the group again and assert the group is not present anymore.
+    $remove_link->click();
+    $assert_session->assertWaitOnAjaxRequest();
+    $remove_link = $page->findLink('Remove group');
+    $this->assertEmpty($remove_link, 'Remove button not available');
+
+    // Add group again to test drag-n-drop.
+    $create_new_filter_group = $page->findById('views-add-group-link');
+    $this->assertTrue($create_new_filter_group->isVisible(), 'Add group link found.');
+    $create_new_filter_group->click();
+    $assert_session->assertWaitOnAjaxRequest();
+
+    // Validate dragging behaviors.
+
+    // First get relevant elements and the current values.
+    $status_extra_row = $page->findById("views-row-status_extra");
+    $langcode_row = $page->findById("views-row-langcode");
+
+    $status_extra_group_field = $status_extra_row->findField('filters[status_extra][group]');
+    $langcode_group_field = $langcode_row->findField('filters[langcode][group]');
+
+    $status_extra_original_value = $status_extra_group_field->getValue();
+    $langcode_original_value = $langcode_group_field->getValue();
+
+    // Validate dragging the first filter works correctly but checking the
+    // remove group link is not visible anymore.
+    $drag_handle = $status_extra_row->find('css', '.tabledrag-handle');
+    $target = $page->find('css', '.filter-group-operator-row');
+    $drag_handle->dragTo($target);
+
+    // Assert dragging a filter works.
+    $remove_link = $page->findLink('Remove group');
+    $this->assertFalse($remove_link->isVisible(), 'Remove group should be invisible after drag.');
+
+    // Drag another filter to the end of the last filter group to verify the
+    // group is set correctly.
+    $drag_handle = $langcode_row->find('css', '.tabledrag-handle');
+    $drag_handle->dragTo($status_extra_row);
+
+    // Both rows must be in the same group.
+    $this->assertNotEquals($status_extra_original_value, $status_extra_group_field->getValue(), 'Status extra group should be changed');
+    $this->assertNotEquals($langcode_original_value, $langcode_group_field->getValue(), 'Langcode group should be changed');
+
+    $this->assertSession()->waitForLink('Create new filter group', 20000);
+    $create_new_filter_group = $page->findLink('Create new filter group');
+    $this->assertTrue($create_new_filter_group->isVisible(), 'Add group link found.');
+    $create_new_filter_group->click();
+    $assert_session->assertWaitOnAjaxRequest();
+
+    // Validate dragging works correctly and the new group will contain the new
+    // filter.
+    $dragged = $page->find('css', ".tabledrag-handle");
+    $target = $page->find('css', '.filter-group-operator-row');
+    $dragged->dragTo($target);
+
+    $remove_link = $page->findLink('Remove group');
+    $this->assertFalse($remove_link->isVisible(), 'Remove group should be invisible after drag.');
+  }
+
+  /**
+   * Tests operator labels.
+   */
+  public function testOperatorLabels(): void {
+    // Open the "Frontpage" view.
+    $this->drupalGet('admin/structure/views/view/frontpage');
+    $session = $this->getSession();
+    $page = $session->getPage();
+
+    // Open the "Rearrange filter criteria" dialog.
+    $this->openFilterDialog();
+
+    // Get the last filter on the list.
+    $row = $page->findAll('css', '.draggable');
+    $row_count = count($row);
+    $last_row = array_pop($row);
+    $penultimate_row = array_pop($row);
+
+    // Drag the last row before the penultimate row.
+    $drag_handle = $last_row->find('css', '.tabledrag-handle');
+    $drag_handle->dragTo($penultimate_row);
+
+    // Assert there are valid number of visible operator labels.
+    $operator_label = $page->findAll('css', '.views-operator-label');
+    $this->assertEquals($row_count - 1, count($operator_label), 'There are valid number of operator labels after drag.');
+
+    // Get the last filter on the rearranged list.
+    $row = $page->findAll('css', '.draggable');
+    $last_row = array_pop($row);
+    $penultimate_row = array_pop($row);
+
+    // Assert the operator label in the penultimate row is shown.
+    $operator_label = $penultimate_row->find('css', '.views-operator-label');
+    $this->assertTrue($operator_label->isVisible(), 'Operator label in the penultimate row is not visible after drag.');
+
+    // Assert the operator label in the last row is not shown.
+    $operator_label = $last_row->find('css', '.views-operator-label');
+    $this->assertNull($operator_label, 'Operator label in the last row is not visible after drag.');
+
+    // Remove the last filter.
+    $remove_link = $last_row->find('css', '.views-remove-link');
+    $remove_link->click();
+
+    // The current last filter shouldn't have the operator label.
+    $operator_label = $penultimate_row->find('css', '.views-operator-label');
+    $this->assertNull($operator_label, 'The penultimate filter has no operator label after the last filter is removed.');
+  }
+
+  /**
+   * Uses the 'And/Or Rearrange' link for filters to open a dialog.
+   */
+  protected function openFilterDialog() {
+    $assert_session = $this->assertSession();
+    $page = $this->getSession()->getPage();
+    $dropbutton = $page->find('css', '.views-ui-display-tab-bucket.filter .dropbutton-toggle button');
+    $dropbutton->click();
+    $add_link = $page->findById('views-rearrange-filter');
+    $this->assertTrue($add_link->isVisible(), 'And/Or Rearrange button found.');
+    $add_link->click();
+    $assert_session->assertWaitOnAjaxRequest();
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/FilterOptionsTest.php

@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Tests the JavaScript filtering of options in add handler form.
+ *
+ * @group views_ui
+ */
+class FilterOptionsTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'views',
+    'views_ui',
+    'views_ui_test_field',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $admin_user = $this->drupalCreateUser([
+      'administer views',
+    ]);
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests filtering options in the 'Add fields' dialog.
+   */
+  public function testFilterOptionsAddFields(): void {
+    $this->drupalGet('admin/structure/views/view/content');
+
+    $session = $this->getSession();
+    $web_assert = $this->assertSession();
+    $page = $session->getPage();
+
+    // Open the dialog.
+    $page->clickLink('views-add-field');
+
+    // Wait for the popup to open and the search field to be available.
+    $options_search = $web_assert->waitForField('override[controls][options_search]');
+
+    // Test that the both special fields are visible.
+    $this->assertTrue($page->findField('name[views.views_test_field_1]')->isVisible());
+    $this->assertTrue($page->findField('name[views.views_test_field_2]')->isVisible());
+
+    // Test the ".title" field in search.
+    $options_search->setValue('FIELD_1_TITLE');
+    $page->waitFor(10, function () use ($page) {
+      return !$page->findField('name[views.views_test_field_2]')->isVisible();
+    });
+    $this->assertTrue($page->findField('name[views.views_test_field_1]')->isVisible());
+    $this->assertFalse($page->findField('name[views.views_test_field_2]')->isVisible());
+
+    // Test the ".description" field in search.
+    $options_search->setValue('FIELD_2_DESCRIPTION');
+    $page->waitFor(10, function () use ($page) {
+      return !$page->findField('name[views.views_test_field_1]')->isVisible();
+    });
+    $this->assertTrue($page->findField('name[views.views_test_field_2]')->isVisible());
+    $this->assertFalse($page->findField('name[views.views_test_field_1]')->isVisible());
+
+    // Test the "label" field not in search.
+    $options_search->setValue('FIELD_1_LABEL');
+    $page->waitFor(10, function () use ($page) {
+      return !$page->findField('name[views.views_test_field_2]')->isVisible();
+    });
+    $this->assertFalse($page->findField('name[views.views_test_field_2]')->isVisible());
+    $this->assertFalse($page->findField('name[views.views_test_field_1]')->isVisible());
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/PreviewTest.php

@@ -0,0 +1,315 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Behat\Mink\Element\NodeElement;
+use Drupal\Core\Database\Database;
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+use Drupal\views\Tests\ViewTestData;
+
+/**
+ * Tests the UI preview functionality.
+ *
+ * @group views_ui
+ */
+class PreviewTest extends WebDriverTestBase {
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_preview', 'test_pager_full_ajax', 'test_mini_pager_ajax', 'test_click_sort_ajax'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'node',
+    'views',
+    'views_ui',
+    'views_test_config',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    ViewTestData::createTestViews(self::class, ['views_test_config']);
+
+    $this->enableViewsTestModule();
+
+    $admin_user = $this->drupalCreateUser([
+      'administer site configuration',
+      'administer views',
+      'administer nodes',
+      'access content overview',
+    ]);
+
+    // Disable automatic live preview to make the sequence of calls clearer.
+    \Drupal::configFactory()->getEditable('views.settings')->set('ui.always_live_preview', FALSE)->save();
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Sets up the views_test_data.module.
+   *
+   * Because the schema of views_test_data.module is dependent on the test
+   * using it, it cannot be enabled normally.
+   */
+  protected function enableViewsTestModule() {
+    // Define the schema and views data variable before enabling the test module.
+    \Drupal::state()->set('views_test_data_schema', $this->schemaDefinition());
+    \Drupal::state()->set('views_test_data_views_data', $this->viewsData());
+
+    \Drupal::service('module_installer')->install(['views_test_data']);
+    $this->resetAll();
+    $this->rebuildContainer();
+    $this->container->get('module_handler')->reload();
+
+    // Load the test dataset.
+    $data_set = $this->dataSet();
+    $query = Database::getConnection()->insert('views_test_data')
+      ->fields(array_keys($data_set[0]));
+    foreach ($data_set as $record) {
+      $query->values($record);
+    }
+    $query->execute();
+  }
+
+  /**
+   * Returns the schema definition.
+   *
+   * @internal
+   */
+  protected function schemaDefinition() {
+    return ViewTestData::schemaDefinition();
+  }
+
+  /**
+   * Returns the views data definition.
+   */
+  protected function viewsData() {
+    return ViewTestData::viewsData();
+  }
+
+  /**
+   * Returns a very simple test dataset.
+   */
+  protected function dataSet() {
+    return ViewTestData::dataSet();
+  }
+
+  /**
+   * Tests the taxonomy term preview AJAX.
+   *
+   * This tests a specific regression in the taxonomy term view preview.
+   *
+   * @see https://www.drupal.org/node/2452659
+   */
+  public function testTaxonomyAJAX(): void {
+    \Drupal::service('module_installer')->install(['taxonomy']);
+    $this->getPreviewAJAX('taxonomy_term', 'page_1', 0);
+  }
+
+  /**
+   * Tests pagers in the preview form.
+   */
+  public function testPreviewWithPagersUI(): void {
+    // Create 11 nodes and make sure that everyone is returned.
+    $this->drupalCreateContentType(['type' => 'page']);
+    for ($i = 0; $i < 11; $i++) {
+      $this->drupalCreateNode();
+    }
+
+    // Test Full Pager.
+    $this->getPreviewAJAX('test_pager_full_ajax', 'default', 5);
+
+    // Test that the pager is present and rendered.
+    $elements = $this->xpath('//ul[contains(@class, "pager__items")]/li');
+    $this->assertNotEmpty($elements);
+
+    // Verify elements and links to pages.
+    // We expect to find 5 elements: current page == 1, links to pages 2 and
+    // and 3, links to 'next >' and 'last >>' pages.
+    $this->assertClass($elements[0], 'is-active', 'Element for current page has .is-active class.');
+    $this->assertNotEmpty($elements[0]->find('css', 'a'), 'Element for current page has link.');
+
+    $this->assertClass($elements[1], 'pager__item', 'Element for page 2 has .pager__item class.');
+    $this->assertNotEmpty($elements[1]->find('css', 'a'), 'Link to page 2 found.');
+
+    $this->assertClass($elements[2], 'pager__item', 'Element for page 3 has .pager__item class.');
+    $this->assertNotEmpty($elements[2]->find('css', 'a'), 'Link to page 3 found.');
+
+    $this->assertClass($elements[3], 'pager__item--next', 'Element for next page has .pager__item--next class.');
+    $this->assertNotEmpty($elements[3]->find('css', 'a'), 'Link to next page found.');
+
+    $this->assertClass($elements[4], 'pager__item--last', 'Element for last page has .pager__item--last class.');
+    $this->assertNotEmpty($elements[4]->find('css', 'a'), 'Link to last page found.');
+
+    // Navigate to next page.
+    $element = $this->assertSession()->elementExists('xpath', '//li[contains(@class, "pager__item--next")]/a');
+    $this->clickPreviewLinkAJAX($element, 5);
+
+    // Test that the pager is present and rendered.
+    $elements = $this->xpath('//ul[contains(@class, "pager__items")]/li');
+    $this->assertNotEmpty($elements);
+
+    // Verify elements and links to pages.
+    // We expect to find 7 elements: links to '<< first' and '< previous'
+    // pages, link to page 1, current page == 2, link to page 3 and links
+    // to 'next >' and 'last >>' pages.
+    $this->assertClass($elements[0], 'pager__item--first', 'Element for first page has .pager__item--first class.');
+    $this->assertNotEmpty($elements[0]->find('css', 'a'), 'Link to first page found.');
+
+    $this->assertClass($elements[1], 'pager__item--previous', 'Element for previous page has .pager__item--previous class.');
+    $this->assertNotEmpty($elements[1]->find('css', 'a'), 'Link to previous page found.');
+
+    $this->assertClass($elements[2], 'pager__item', 'Element for page 1 has .pager__item class.');
+    $this->assertNotEmpty($elements[2]->find('css', 'a'), 'Link to page 1 found.');
+
+    $this->assertClass($elements[3], 'is-active', 'Element for current page has .is-active class.');
+    $this->assertNotEmpty($elements[3]->find('css', 'a'), 'Element for current page has link.');
+
+    $this->assertClass($elements[4], 'pager__item', 'Element for page 3 has .pager__item class.');
+    $this->assertNotEmpty($elements[4]->find('css', 'a'), 'Link to page 3 found.');
+
+    $this->assertClass($elements[5], 'pager__item--next', 'Element for next page has .pager__item--next class.');
+    $this->assertNotEmpty($elements[5]->find('css', 'a'), 'Link to next page found.');
+
+    $this->assertClass($elements[6], 'pager__item--last', 'Element for last page has .pager__item--last class.');
+    $this->assertNotEmpty($elements[6]->find('css', 'a'), 'Link to last page found.');
+
+    // Test Mini Pager.
+    $this->getPreviewAJAX('test_mini_pager_ajax', 'default', 3);
+
+    // Test that the pager is present and rendered.
+    $elements = $this->xpath('//ul[contains(@class, "pager__items")]/li');
+    $this->assertNotEmpty($elements);
+
+    // Verify elements and links to pages.
+    // We expect to find current pages element with no link, next page element
+    // with a link, and not to find previous page element.
+    $this->assertEquals('Page 1', trim($elements[0]->getHtml()), 'Element for current page is not a link.');
+
+    $next_page_link = $elements[1]->find('css', 'a');
+    $this->assertNotEmpty($next_page_link, 'Link to next page found.');
+    $this->assertEquals('Go to next page', $next_page_link->getAttribute('title'));
+
+    // Navigate to next page.
+    $this->clickPreviewLinkAJAX($next_page_link, 3);
+
+    // Test that the pager is present and rendered.
+    $elements = $this->xpath('//ul[contains(@class, "pager__items")]/li');
+    $this->assertNotEmpty($elements);
+
+    // Verify elements and links to pages.
+    // We expect to find 3 elements: previous page with a link, current
+    // page with no link, and next page with a link.
+    $previous_page_link = $elements[0]->find('css', 'a');
+    $this->assertNotEmpty($previous_page_link, 'Link to previous page found.');
+    $this->assertEquals('Go to previous page', $previous_page_link->getAttribute('title'));
+
+    $this->assertEquals('Page 2', trim($elements[1]->getHtml()), 'Element for current page is not a link.');
+
+    $next_page_link = $elements[2]->find('css', 'a');
+    $this->assertNotEmpty($next_page_link, 'Link to next page found.');
+    $this->assertEquals('Go to next page', $next_page_link->getAttribute('title'));
+  }
+
+  /**
+   * Tests the link to sort in the preview form.
+   */
+  public function testPreviewSortLink(): void {
+    // Get the preview.
+    $this->getPreviewAJAX('test_click_sort_ajax', 'page_1', 0);
+
+    // Test that the header label is present.
+    $element = $this->assertSession()->elementExists('xpath', '//th[contains(@class, "views-field views-field-name")]/a');
+
+    // Verify link.
+    $this->assertSession()->linkByHrefExists('preview/page_1?_wrapper_format=drupal_ajax&order=name&sort=desc', 0, 'The output URL is as expected.');
+
+    // Click link to sort.
+    $element->click();
+    $sort_link = $this->assertSession()->waitForElement('xpath', '//th[contains(@class, \'views-field views-field-name is-active\')]/a');
+
+    $this->assertNotEmpty($sort_link);
+
+    // Verify link.
+    $this->assertSession()->linkByHrefExists('preview/page_1?_wrapper_format=drupal_ajax&order=name&sort=asc', 0, 'The output URL is as expected.');
+  }
+
+  /**
+   * Get the preview form and force an AJAX preview update.
+   *
+   * @param string $view_name
+   *   The view to test.
+   * @param string $panel_id
+   *   The view panel to test.
+   * @param int $row_count
+   *   The expected number of rows in the preview.
+   */
+  protected function getPreviewAJAX($view_name, $panel_id, $row_count) {
+    $this->drupalGet('admin/structure/views/view/' . $view_name . '/edit/' . $panel_id);
+    $this->getSession()->getPage()->pressButton('Update preview');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertPreviewAJAX($row_count);
+  }
+
+  /**
+   * Click on a preview link.
+   *
+   * @param \Behat\Mink\Element\NodeElement $element
+   *   The element to click.
+   * @param int $row_count
+   *   The expected number of rows in the preview.
+   */
+  protected function clickPreviewLinkAJAX(NodeElement $element, $row_count) {
+    $element->click();
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertPreviewAJAX($row_count);
+  }
+
+  /**
+   * Assert that the preview contains expected data.
+   *
+   * @param int $row_count
+   *   The expected number of rows in the preview.
+   *
+   * @internal
+   */
+  protected function assertPreviewAJAX(int $row_count): void {
+    $elements = $this->getSession()->getPage()->findAll('css', '#views-live-preview .views-row');
+    $this->assertCount($row_count, $elements, 'Expected items found on page.');
+  }
+
+  /**
+   * Asserts that an element has a given class.
+   *
+   * @param \Behat\Mink\Element\NodeElement $element
+   *   The element to test.
+   * @param string $class
+   *   The class to assert.
+   * @param string $message
+   *   (optional) A verbose message to output.
+   *
+   * @internal
+   */
+  protected function assertClass(NodeElement $element, string $class, string $message = ''): void {
+    if (!isset($message)) {
+      $message = "Class .$class found.";
+    }
+    $this->assertStringContainsString($class, $element->getAttribute('class'), $message);
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/ViewsListingTest.php

@@ -0,0 +1,149 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Tests the JavaScript filtering on the Views listing page.
+ *
+ * @see core/modules/views_ui/js/views_ui.listing.js
+ * @group views_ui
+ */
+class ViewsListingTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['node', 'views', 'views_ui'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $admin_user = $this->drupalCreateUser([
+      'administer site configuration',
+      'administer views',
+    ]);
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests the filtering on the Views listing page.
+   */
+  public function testFilterViewsListing(): void {
+    $enabled_views_count = 6;
+    $disabled_views_count = 2;
+    $content_views_count = 3;
+
+    $this->drupalGet('admin/structure/views');
+
+    $session = $this->assertSession();
+
+    $page = $this->getSession()->getPage();
+
+    // Test that we search in both the enabled and disabled rows.
+    $enabled_rows = $page->findAll('css', 'tr.views-ui-list-enabled');
+    $enabled_rows = $this->filterVisibleElements($enabled_rows);
+    $disabled_rows = $page->findAll('css', 'tr.views-ui-list-disabled');
+    $disabled_rows = $this->filterVisibleElements($disabled_rows);
+
+    // Test that we see some rows of views in both tables.
+    $this->assertCount($enabled_views_count, $enabled_rows);
+    $this->assertCount($disabled_views_count, $disabled_rows);
+
+    // Filter on the string 'people'. This should only show the people view.
+    $search_input = $page->find('css', '.views-filter-text.form-search');
+    $search_input->setValue('people');
+
+    $enabled_rows = $page->findAll('css', 'tr.views-ui-list-enabled');
+    $enabled_rows = $this->filterVisibleElements($enabled_rows);
+    $disabled_rows = $page->findAll('css', 'tr.views-ui-list-disabled');
+    $disabled_rows = $this->filterVisibleElements($disabled_rows);
+
+    $this->assertCount(1, $enabled_rows);
+    $this->assertCount(0, $disabled_rows);
+
+    // Filter on a string that also appears in the description.
+    $search_input->setValue('content');
+
+    $enabled_rows = $page->findAll('css', 'tr.views-ui-list-enabled');
+    $enabled_rows = $this->filterVisibleElements($enabled_rows);
+    $disabled_rows = $page->findAll('css', 'tr.views-ui-list-disabled');
+    $disabled_rows = $this->filterVisibleElements($disabled_rows);
+
+    $this->assertCount($content_views_count, $enabled_rows);
+    $this->assertCount($disabled_views_count, $disabled_rows);
+
+    // Reset the search string and check that we are back to the initial stage.
+    $search_input->setValue('');
+    // Add a backspace to trigger the keyUp event.
+    $search_input->keyUp(8);
+
+    $enabled_rows = $page->findAll('css', 'tr.views-ui-list-enabled');
+    $enabled_rows = $this->filterVisibleElements($enabled_rows);
+    $disabled_rows = $page->findAll('css', 'tr.views-ui-list-disabled');
+    $disabled_rows = $this->filterVisibleElements($disabled_rows);
+
+    $this->assertCount($enabled_views_count, $enabled_rows);
+    $this->assertCount($disabled_views_count, $disabled_rows);
+
+    // Disable a View and see if it moves to the disabled listing.
+    $enabled_view = $page->find('css', 'tr.views-ui-list-enabled');
+    $view_description = $enabled_view->find('css', '.views-ui-view-name strong')->getText();
+    // Open the dropdown with additional actions.
+    $enabled_view->find('css', 'li.dropbutton-toggle button')->click();
+    $disable_button = $enabled_view->findLink('Disable');
+    // Check that the disable button is visible now.
+    $this->assertTrue($disable_button->isVisible());
+    $disable_button->click();
+
+    $session->assertWaitOnAjaxRequest();
+
+    $enabled_rows = $page->findAll('css', 'tr.views-ui-list-enabled');
+    $enabled_rows = $this->filterVisibleElements($enabled_rows);
+    $disabled_rows = $page->findAll('css', 'tr.views-ui-list-disabled');
+    $disabled_rows = $this->filterVisibleElements($disabled_rows);
+
+    // Test that one enabled View has been moved to the disabled list.
+    $this->assertCount($enabled_views_count - 1, $enabled_rows);
+    $this->assertCount($disabled_views_count + 1, $disabled_rows);
+
+    // Test that the keyboard focus is on the dropdown button of the View we
+    // just disabled.
+    $this->assertTrue($this->getSession()->evaluateScript("jQuery(document.activeElement).text() === 'Enable'"));
+    $this->assertEquals($view_description, $this->getSession()->evaluateScript("jQuery(document.activeElement).parents('tr').find('.views-ui-view-name strong').text()"));
+
+    // Enable the view again and ensure we have the focus on the edit button.
+    $this->getSession()->evaluateScript('jQuery(document.activeElement).click()');
+    $session->assertWaitOnAjaxRequest();
+
+    $this->assertTrue($this->getSession()->evaluateScript("jQuery(document.activeElement).text() === 'Edit'"));
+    $this->assertEquals($view_description, $this->getSession()->evaluateScript("jQuery(document.activeElement).parents('tr').find('.views-ui-view-name strong').text()"));
+  }
+
+  /**
+   * Removes any non-visible elements from the passed array.
+   *
+   * @param array $elements
+   *   The elements.
+   *
+   * @return array
+   */
+  protected function filterVisibleElements($elements) {
+    $elements = array_filter($elements, function ($element) {
+      return $element->isVisible();
+    });
+    return $elements;
+  }
+
+}

core/modules/views_ui/tests/src/FunctionalJavascript/ViewsWizardTest.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\FunctionalJavascript;
+
+use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
+
+/**
+ * Tests views creation wizard.
+ *
+ * @see core/modules/views_ui/js/views-admin.js
+ * @group views_ui
+ */
+class ViewsWizardTest extends WebDriverTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['node', 'views', 'views_ui', 'block', 'user'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $admin_user = $this->drupalCreateUser([
+      'access administration pages',
+      'administer views',
+    ]);
+    $this->drupalLogin($admin_user);
+  }
+
+  /**
+   * Tests creating a View using the wizard.
+   */
+  public function testCreateViewWizard(): void {
+    $this->drupalGet('admin/structure/views/add');
+    $page = $this->getSession()->getPage();
+
+    // Set a view name, this should be used to prepopulate a number of other
+    // fields when creating displays.
+    $label_value = 'test view';
+    $search_input = $page->findField('label');
+    $search_input->setValue($label_value);
+
+    $page->findField('page[create]')->click();
+
+    // Test if the title and path have been populated.
+    $this->assertEquals($label_value, $page->findField('page[title]')->getValue());
+    $this->assertEquals(str_replace(' ', '-', $label_value), $page->findField('page[path]')->getValue());
+
+    // Create a menu item.
+    $page->findField('page[link]')->click();
+    $this->assertEquals($label_value, $page->findField('page[link_properties][title]')->getValue());
+
+    // Wait for conditional field to show.
+    $this->assertSession()->waitForElementVisible('named', ['select', 'page[link_properties][parent]']);
+
+    // Assert a menu can be selected as a parent.
+    $this->assertSession()->optionExists('page[link_properties][parent]', 'admin:');
+
+    // Assert a parent menu item can be selected from within a menu.
+    $this->assertSession()->optionExists('page[link_properties][parent]', 'admin:entity.view.collection');
+
+    // Add a block display.
+    $page->findField('block[create]')->click();
+    $this->assertEquals($label_value, $page->findField('block[title]')->getValue());
+
+    // Select the entity type to display and test that the type selector is
+    // shown when expected.
+    $this->assertSame('node', $page->findField('show[wizard_key]')->getValue());
+    $this->assertNull($page->findField('show[type]'), 'The "of type" filter is not added for nodes when there are no node types.');
+    $this->assertEquals('teasers', $page->findField('page[style][row_plugin]')->getValue(), 'The page display format shows the expected default value.');
+    $this->assertEquals('titles_linked', $page->findField('block[style][row_plugin]')->getValue(), 'The block display format shows the expected default value.');
+
+    $page->selectFieldOption('show[wizard_key]', 'users');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertNull($page->findField('show[type]'), 'The "of type" filter is not added for users.');
+    $this->assertEquals('fields', $page->findField('page[style][row_plugin]')->getValue(), 'The page display format was updated to a valid value.');
+    $this->assertEquals('fields', $page->findField('block[style][row_plugin]')->getValue(), 'The block display format was updated to a valid value.');
+
+    $this->drupalCreateContentType(['type' => 'page']);
+    $page->selectFieldOption('show[wizard_key]', 'node');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertNotNull($page->findField('show[type]'), 'The "of type" filter is added for nodes when there is at least one node type.');
+    $this->assertEquals('fields', $page->findField('page[style][row_plugin]')->getValue(), 'The page display format was not changed from a valid value.');
+    $this->assertEquals('fields', $page->findField('block[style][row_plugin]')->getValue(), 'The block display format was not changed from a valid value.');
+  }
+
+}

core/modules/views_ui/tests/src/Kernel/TagTest.php

@@ -0,0 +1,119 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Kernel;
+
+use Drupal\Tests\views\Kernel\ViewsKernelTestBase;
+use Drupal\views_ui\Controller\ViewsUIController;
+use Drupal\Component\Utility\Html;
+use Drupal\views\Entity\View;
+
+/**
+ * Tests the views ui tagging functionality.
+ *
+ * @group views_ui
+ * @group #slow
+ */
+class TagTest extends ViewsKernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views', 'views_ui', 'user'];
+
+  /**
+   * Tests the ViewsUIController::autocompleteTag() function.
+   */
+  public function testViewsUiAutocompleteTag(): void {
+    \Drupal::moduleHandler()->loadInclude('views_ui', 'inc', 'admin');
+
+    // Save 15 views with a tag.
+    $tags = [];
+    for ($i = 0; $i < 16; $i++) {
+      $suffix = $i % 2 ? 'odd' : 'even';
+      $tag = 'autocomplete_tag_test_' . $suffix . $this->randomMachineName();
+      $tags[] = $tag;
+      View::create([
+        'tag' => $tag,
+        'id' => $this->randomMachineName(),
+        'label' => 'Test',
+      ])->save();
+    }
+
+    // Make sure just ten results are returned.
+    $controller = ViewsUIController::create($this->container);
+    $request = $this->container->get('request_stack')->getCurrentRequest();
+    $request->query->set('q', 'autocomplete_tag_test');
+    $result = $controller->autocompleteTag($request);
+    $matches = (array) json_decode($result->getContent(), TRUE);
+    $this->assertCount(10, $matches, 'Make sure the maximum amount of tag results is 10.');
+
+    // Make sure the returned array has the proper format.
+    $suggestions = array_map(function ($tag) {
+      return ['value' => $tag, 'label' => Html::escape($tag)];
+    }, $tags);
+    foreach ($matches as $match) {
+      $this->assertContains($match, $suggestions, 'Make sure the returned array has the proper format.');
+    }
+
+    // Make sure that matching by a certain prefix works.
+    $request->query->set('q', 'autocomplete_tag_test_even');
+    $result = $controller->autocompleteTag($request);
+    $matches = (array) json_decode($result->getContent(), TRUE);
+    $this->assertCount(8, $matches, 'Make sure that only a subset is returned.');
+    foreach ($matches as $tag) {
+      $this->assertContains($tag['value'], $tags);
+    }
+
+    // Make sure an invalid result doesn't return anything.
+    $request->query->set('q', $this->randomMachineName());
+    $result = $controller->autocompleteTag($request);
+    $matches = (array) json_decode($result->getContent());
+    $this->assertCount(0, $matches, "Make sure an invalid tag doesn't return anything.");
+  }
+
+  /**
+   * Tests that comma delimited tags are treated as individual tags.
+   *
+   * @dataProvider providerViewsUiAutocompleteIndividualTags
+   */
+  public function testViewsUiAutocompleteIndividualTags($expected_tag, $search_string): void {
+    $controller = ViewsUIController::create($this->container);
+    $request = $this->container->get('request_stack')->getCurrentRequest();
+    $tag = 'comma, 你好, Foo bar';
+    View::create([
+      'tag' => $tag,
+      'id' => $this->randomMachineName(),
+      'label' => 'Test',
+    ])->save();
+    $request->query->set('q', $search_string);
+    $result = $controller->autocompleteTag($request);
+    $matches = (array) json_decode($result->getContent());
+    $this->assertCount(1, $matches);
+    $this->assertSame($expected_tag, $matches[0]->value);
+  }
+
+  /**
+   * Data provider for testViewsUiAutocompleteIndividualTags().
+   *
+   * @return array[]
+   *   The data set.
+   */
+  public static function providerViewsUiAutocompleteIndividualTags() {
+    return [
+      'tag' => ['comma', 'comma'],
+      'case insensitive tag' => ['comma', 'COMMA'],
+      'Hello in Chinese (partial 1)' => ['你好', '你'],
+      'Hello in Chinese (partial 2)' => ['你好', '好'],
+      'Hello in Chinese' => ['你好', '你好'],
+      'Starts with partial and case-sensitive' => ['Foo bar', 'Foo'],
+      'Starts with partial and case-insensitive' => ['Foo bar', 'fOO'],
+      'Ends with partial and case-sensitive' => ['Foo bar', 'bar'],
+      'Ends with partial and case-insensitive' => ['Foo bar', 'BAR'],
+    ];
+  }
+
+}

core/modules/views_ui/tests/src/Kernel/TruncateDeprecateTest.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Kernel;
+
+use Drupal\Tests\views\Kernel\ViewsKernelTestBase;
+
+/**
+ * Tests the deprecation of views_ui_truncate() function.
+ *
+ * @group views_ui
+ */
+class TruncateDeprecateTest extends ViewsKernelTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = ['views', 'views_ui'];
+
+  /**
+   * Tests the deprecation of views_ui_truncate() replaced by Unicode::truncate.
+   *
+   * @group legacy
+   */
+  public function testDeprecateViewsUiTruncate(): void {
+    $string = 'one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen';
+    $short_string = views_ui_truncate($string, 80);
+    $this->expectDeprecation('views_ui_truncate() is deprecated in drupal:10.3.0 and is removed from drupal:12.0.0. Use \Drupal\Component\Utility\Unicode::truncate(). See https://www.drupal.org/node/3408283');
+  }
+
+}

core/modules/views_ui/tests/src/Kernel/ViewsBlockTest.php

@@ -0,0 +1,82 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Kernel;
+
+use Drupal\Core\Url;
+use Drupal\block\Entity\Block;
+use Drupal\Tests\user\Traits\UserCreationTrait;
+use Drupal\Tests\views\Kernel\ViewsKernelTestBase;
+use Drupal\views\Tests\ViewTestData;
+
+/**
+ * Tests ViewsBlock.
+ *
+ * @group views_ui
+ */
+class ViewsBlockTest extends ViewsKernelTestBase {
+
+  use UserCreationTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'system',
+    'block',
+    'block_test_views',
+    'views_ui',
+    'user',
+  ];
+
+  /**
+   * Views used by this test.
+   *
+   * @var array
+   */
+  public static $testViews = ['test_view_block'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp($import_test_views = TRUE): void {
+    parent::setUp();
+
+    ViewTestData::createTestViews(static::class, ['block_test_views']);
+  }
+
+  /**
+   * Tests the editing links for ViewsBlockBase.
+   */
+  public function testOperationLinks(): void {
+    $this->setUpCurrentUser(['uid' => 0]);
+
+    $block = Block::create([
+      'plugin' => 'views_block:test_view_block-block_1',
+      'region' => 'content',
+      'id' => 'machine_name',
+      'theme' => 'stark',
+    ]);
+
+    // The anonymous user doesn't have the "administer block" permission.
+    $this->assertEmpty(views_ui_entity_operation($block));
+
+    $this->setUpCurrentUser(['uid' => 1], ['administer views']);
+
+    // The admin user does have the "administer block" permission.
+    $this->assertEquals([
+      'view-edit' => [
+        'title' => 'Edit view',
+        'url' => Url::fromRoute('entity.view.edit_display_form', [
+          'view' => 'test_view_block',
+          'display_id' => 'block_1',
+        ]),
+        'weight' => 50,
+      ],
+    ], views_ui_entity_operation($block));
+  }
+
+}

core/modules/views_ui/tests/src/Unit/Form/Ajax/RearrangeFilterTest.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Unit\Form\Ajax;
+
+use Drupal\Tests\UnitTestCase;
+use Drupal\views_ui\Form\Ajax\RearrangeFilter;
+
+/**
+ * Unit tests for Views UI module functions.
+ *
+ * @group views_ui
+ */
+class RearrangeFilterTest extends UnitTestCase {
+
+  /**
+   * Tests static methods.
+   */
+  public function testStaticMethods(): void {
+    // Test the RearrangeFilter::arrayKeyPlus method.
+    $original = [0 => 'one', 1 => 'two', 2 => 'three'];
+    $expected = [1 => 'one', 2 => 'two', 3 => 'three'];
+    $this->assertSame(RearrangeFilter::arrayKeyPlus($original), $expected);
+  }
+
+}

core/modules/views_ui/tests/src/Unit/ViewListBuilderTest.php

@@ -0,0 +1,198 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Unit;
+
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Menu\MenuParentFormSelector;
+use Drupal\Tests\UnitTestCase;
+use Drupal\views\Entity\View;
+use Drupal\views\ViewExecutableFactory;
+use Drupal\views_ui\ViewListBuilder;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\RequestStack;
+
+/**
+ * @coversDefaultClass \Drupal\views_ui\ViewListBuilder
+ * @group views_ui
+ */
+class ViewListBuilderTest extends UnitTestCase {
+
+  /**
+   * Tests the listing of displays on a views list builder.
+   *
+   * @see \Drupal\views_ui\ViewListBuilder::getDisplaysList()
+   * @covers ::buildRow
+   */
+  public function testBuildRowEntityList(): void {
+    $storage = $this->getMockBuilder('Drupal\Core\Config\Entity\ConfigEntityStorage')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $display_manager = $this->getMockBuilder('\Drupal\views\Plugin\ViewsPluginManager')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $display_manager->expects($this->any())
+      ->method('getDefinition')
+      ->willReturnMap([
+        [
+          'default',
+          TRUE,
+          [
+            'id' => 'default',
+            'title' => 'Default',
+            'theme' => 'views_view',
+            'no_ui' => TRUE,
+            'admin' => '',
+          ],
+        ],
+        [
+          'page',
+          TRUE,
+          [
+            'id' => 'page',
+            'title' => 'Page',
+            'uses_menu_links' => TRUE,
+            'uses_route' => TRUE,
+            'contextual_links_locations' => ['page'],
+            'theme' => 'views_view',
+            'admin' => 'Page admin label',
+          ],
+        ],
+        [
+          'embed',
+          TRUE,
+          [
+            'id' => 'embed',
+            'title' => 'embed',
+            'theme' => 'views_view',
+            'admin' => 'Embed admin label',
+          ],
+        ],
+      ]);
+
+    $default_display = $this->getMockBuilder('Drupal\views\Plugin\views\display\DefaultDisplay')
+      ->onlyMethods(['initDisplay'])
+      ->setConstructorArgs([[], 'default', $display_manager->getDefinition('default')])
+      ->getMock();
+    $route_provider = $this->createMock('Drupal\Core\Routing\RouteProviderInterface');
+    $state = $this->createMock('\Drupal\Core\State\StateInterface');
+    $menu_storage = $this->createMock('\Drupal\Core\Entity\EntityStorageInterface');
+    $parent_form_selector = $this->createMock(MenuParentFormSelector::class);
+    $page_display = $this->getMockBuilder('Drupal\views\Plugin\views\display\Page')
+      ->onlyMethods(['initDisplay', 'getPath'])
+      ->setConstructorArgs([[], 'default', $display_manager->getDefinition('page'), $route_provider, $state, $menu_storage, $parent_form_selector])
+      ->getMock();
+    $page_display->expects($this->any())
+      ->method('getPath')
+      ->willReturnOnConsecutiveCalls(
+        'test_page',
+        '<object>malformed_path</object>',
+        '<script>alert("placeholder_page/%")</script>',
+      );
+
+    $embed_display = $this->getMockBuilder('Drupal\views\Plugin\views\display\Embed')
+      ->onlyMethods(['initDisplay'])
+      ->setConstructorArgs([[], 'default', $display_manager->getDefinition('embed')])
+      ->getMock();
+
+    $values = [];
+    $values['label'] = 'Test';
+    $values['status'] = FALSE;
+    $values['display']['default']['id'] = 'default';
+    $values['display']['default']['display_title'] = 'Display';
+    $values['display']['default']['display_plugin'] = 'default';
+
+    $values['display']['page_1']['id'] = 'page_1';
+    $values['display']['page_1']['display_title'] = 'Page 1';
+    $values['display']['page_1']['display_plugin'] = 'page';
+    $values['display']['page_1']['display_options']['path'] = 'test_page';
+
+    $values['display']['page_2']['id'] = 'page_2';
+    $values['display']['page_2']['display_title'] = 'Page 2';
+    $values['display']['page_2']['display_plugin'] = 'page';
+    $values['display']['page_2']['display_options']['path'] = '<object>malformed_path</object>';
+
+    $values['display']['page_3']['id'] = 'page_3';
+    $values['display']['page_3']['display_title'] = 'Page 3';
+    $values['display']['page_3']['display_plugin'] = 'page';
+    $values['display']['page_3']['display_options']['path'] = '<script>alert("placeholder_page/%")</script>';
+
+    $values['display']['embed']['id'] = 'embed';
+    $values['display']['embed']['display_title'] = 'Embedded';
+    $values['display']['embed']['display_plugin'] = 'embed';
+
+    $display_manager->expects($this->any())
+      ->method('createInstance')
+      ->willReturnMap([
+        ['default', $values['display']['default'], $default_display],
+        ['page', $values['display']['page_1'], $page_display],
+        ['page', $values['display']['page_2'], $page_display],
+        ['page', $values['display']['page_3'], $page_display],
+        ['embed', $values['display']['embed'], $embed_display],
+      ]);
+
+    $container = new ContainerBuilder();
+    $user = $this->createMock('Drupal\Core\Session\AccountInterface');
+    $request_stack = new RequestStack();
+    $request_stack->push(new Request());
+    $views_data = $this->getMockBuilder('Drupal\views\ViewsData')
+      ->disableOriginalConstructor()
+      ->getMock();
+    $route_provider = $this->createMock('Drupal\Core\Routing\RouteProviderInterface');
+    $executable_factory = new ViewExecutableFactory($user, $request_stack, $views_data, $route_provider, $display_manager);
+    $entity_type_manager = $this->prophesize(EntityTypeManagerInterface::class);
+    $container->set('views.executable', $executable_factory);
+    $container->set('plugin.manager.views.display', $display_manager);
+    $container->set('entity_type.manager', $entity_type_manager->reveal());
+    \Drupal::setContainer($container);
+
+    // Setup a view list builder with a mocked buildOperations method,
+    // because t() is called on there.
+    $entity_type = $this->createMock('Drupal\Core\Entity\EntityTypeInterface');
+    $entity_type_manager->getDefinition('view')->willReturn($entity_type);
+    $view_list_builder = new TestViewListBuilder($entity_type, $storage, $display_manager);
+    $view_list_builder->setStringTranslation($this->getStringTranslationStub());
+
+    // Create new view with test values.
+    $view = new View($values, 'view');
+
+    // Get the row object created by ViewListBuilder for this test view.
+    $row = $view_list_builder->buildRow($view);
+
+    // Expected output array for view's displays.
+    $expected_displays = [
+      '0' => [
+        'display' => 'Embed admin label',
+        'path' => FALSE,
+      ],
+      '1' => [
+        'display' => 'Page admin label',
+        'path' => '/<object>malformed_path</object>',
+      ],
+      '2' => [
+        'display' => 'Page admin label',
+        'path' => '/<script>alert("placeholder_page/%")</script>',
+      ],
+      '3' => [
+        'display' => 'Page admin label',
+        'path' => '/test_page',
+      ],
+    ];
+
+    // Compare the expected and generated output.
+    $this->assertEquals($expected_displays, $row['data']['displays']['data']['#displays']);
+  }
+
+}
+
+class TestViewListBuilder extends ViewListBuilder {
+
+  public function buildOperations(EntityInterface $entity) {
+    return [];
+  }
+
+}

core/modules/views_ui/tests/src/Unit/ViewUIObjectTest.php

@@ -0,0 +1,140 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\views_ui\Unit;
+
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\TempStore\Lock;
+use Drupal\Tests\UnitTestCase;
+use Drupal\views\Entity\View;
+use Drupal\views_ui\ViewUI;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+/**
+ * @coversDefaultClass \Drupal\views_ui\ViewUI
+ * @group views_ui
+ */
+class ViewUIObjectTest extends UnitTestCase {
+
+  /**
+   * Tests entity method decoration.
+   */
+  public function testEntityDecoration(): void {
+    $method_args = [];
+    $method_args['setOriginalId'] = [12];
+    $method_args['setStatus'] = [TRUE];
+    $method_args['enforceIsNew'] = [FALSE];
+    $method_args['label'] = [LanguageInterface::LANGCODE_NOT_SPECIFIED];
+
+    $reflection = new \ReflectionClass('Drupal\Core\Config\Entity\ConfigEntityInterface');
+    $interface_methods = [];
+    foreach ($reflection->getMethods() as $reflection_method) {
+      $interface_methods[] = $reflection_method->getName();
+
+      // EntityInterface::isNew() is missing from the list of methods, because it
+      // calls id(), which breaks the ->expect($this->once()) call. Call it later.
+      // EntityInterface::isSyncing() is only called during syncing process.
+      // EntityInterface::isUninstalling() is only called during uninstallation
+      // process. EntityInterface::getConfigDependencyName() and
+      // ConfigEntityInterface::calculateDependencies() are only used for
+      // dependency management.
+      if (!in_array($reflection_method->getName(), ['isNew', 'isSyncing', 'isUninstalling', 'getConfigDependencyKey', 'getConfigDependencyName', 'calculateDependencies'])) {
+        if (count($reflection_method->getParameters()) == 0) {
+          $method_args[$reflection_method->getName()] = [];
+        }
+      }
+    }
+
+    $storage = $this->getMockBuilder('Drupal\views\Entity\View')
+      ->onlyMethods($interface_methods)
+      ->setConstructorArgs([[], 'view'])
+      ->getMock();
+    $executable = $this->getMockBuilder('Drupal\views\ViewExecutable')
+      ->disableOriginalConstructor()
+      ->setConstructorArgs([$storage])
+      ->getMock();
+    $storage->set('executable', $executable);
+
+    $view_ui = new ViewUI($storage);
+
+    foreach ($method_args as $method => $args) {
+      $method_mock = $storage->expects($this->once())
+        ->method($method);
+      foreach ($args as $arg) {
+        $method_mock->with($this->equalTo($arg));
+      }
+      call_user_func_array([$view_ui, $method], $args);
+    }
+
+    $storage->expects($this->once())
+      ->method('isNew');
+    $view_ui->isNew();
+  }
+
+  /**
+   * Tests the isLocked method.
+   */
+  public function testIsLocked(): void {
+    $storage = $this->getMockBuilder('Drupal\views\Entity\View')
+      ->setConstructorArgs([[], 'view'])
+      ->getMock();
+    $executable = $this->getMockBuilder('Drupal\views\ViewExecutable')
+      ->disableOriginalConstructor()
+      ->setConstructorArgs([$storage])
+      ->getMock();
+    $storage->set('executable', $executable);
+    $account = $this->createMock('Drupal\Core\Session\AccountInterface');
+    $account->expects($this->exactly(2))
+      ->method('id')
+      ->willReturn(1);
+
+    $container = new ContainerBuilder();
+    $container->set('current_user', $account);
+    \Drupal::setContainer($container);
+
+    $view_ui = new ViewUI($storage);
+
+    // A view_ui without a lock object is not locked.
+    $this->assertFalse($view_ui->isLocked());
+
+    // Set the lock object with a different owner than the mocked account above.
+    $lock = new Lock(2, (int) $_SERVER['REQUEST_TIME']);
+    $view_ui->setLock($lock);
+    $this->assertTrue($view_ui->isLocked());
+
+    // Set a different lock object with the same object as the mocked account.
+    $lock = new Lock(1, (int) $_SERVER['REQUEST_TIME']);
+    $view_ui->setLock($lock);
+    $this->assertFalse($view_ui->isLocked());
+
+    $view_ui->unsetLock(NULL);
+    $this->assertFalse($view_ui->isLocked());
+  }
+
+  /**
+   * Tests serialization of the ViewUI object.
+   */
+  public function testSerialization(): void {
+    $storage = new View([], 'view');
+    $executable = $this->getMockBuilder('Drupal\views\ViewExecutable')
+      ->disableOriginalConstructor()
+      ->setConstructorArgs([$storage])
+      ->getMock();
+    $storage->set('executable', $executable);
+
+    $view_ui = new ViewUI($storage);
+
+    // Make sure the executable is returned before serializing.
+    $this->assertInstanceOf('Drupal\views\ViewExecutable', $view_ui->getExecutable());
+
+    $serialized = serialize($view_ui);
+
+    // Make sure the ViewExecutable class is not found in the serialized string.
+    $this->assertStringNotContainsString('"Drupal\views\ViewExecutable"', $serialized);
+
+    $unserialized = unserialize($serialized);
+    $this->assertInstanceOf('Drupal\views_ui\ViewUI', $unserialized);
+  }
+
+}

core/modules/views_ui/tests/themes/views_ui_test_theme/views_ui_test_theme.info.yml

@@ -0,0 +1,11 @@
+name: 'Views UI Test Theme'
+type: theme
+description: 'Test theme for testing Views UI.'
+# version: VERSION
+base theme: stark
+package: Testing
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/views_ui/tests/themes/views_ui_test_theme/views_ui_test_theme.theme

@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * @file
+ * Implements Views UI alter hooks in a theme to provide test coverage.
+ */
+
+use Drupal\views_ui\ViewUI;
+
+/**
+ * Implements hook_views_ui_display_tab_alter().
+ */
+function views_ui_test_theme_views_ui_display_tab_alter(&$build, ViewUI $view, $display_id) {
+  $build['details']['top']['display_title']['#description'] = 'This is text added to the display edit form';
+}
+
+/**
+ * Implements hook_views_ui_display_top_alter().
+ */
+function views_ui_test_theme_views_ui_display_top_alter(&$build, ViewUI $view, $display_id) {
+  $build['tabs']['#suffix'] .= 'This is text added to the display tabs at the top';
+}