first commit

core/modules/help/tests/fixtures/update/drupal-10.access-help-pages.php

@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @file
+ * Contains database additions for testing the help module permission.
+ */
+
+use Drupal\Core\Database\Database;
+use Drupal\Core\Serialization\Yaml;
+
+$connection = Database::getConnection();
+
+$role = Yaml::decode(file_get_contents(__DIR__ . '/drupal-10.access-help-pages.yml'));
+$connection->insert('config')
+  ->fields([
+    'collection',
+    'name',
+    'data',
+  ])
+  ->values([
+    'collection' => '',
+    'name' => 'user.role.content_editor',
+    'data' => serialize($role),
+  ])
+  ->execute();

core/modules/help/tests/fixtures/update/drupal-10.access-help-pages.yml

@@ -0,0 +1,46 @@
+uuid: 91cd52b8-a979-426b-9761-039a5a184b74
+langcode: en
+status: true
+dependencies:
+  config:
+    - node.type.article
+    - node.type.page
+    - taxonomy.vocabulary.tags
+  module:
+    - comment
+    - contextual
+    - file
+    - node
+    - path
+    - system
+    - taxonomy
+    - toolbar
+_core:
+  default_config_hash: Wur9kcEOwY1Jal81NssKnz3RhVJxAvBwyWQBGcA_1Go
+id: content_editor
+label: 'Content editor'
+weight: 2
+is_admin: false
+permissions:
+  - 'access administration pages'
+  - 'access content overview'
+  - 'access contextual links'
+  - 'access files overview'
+  - 'access toolbar'
+  - 'administer url aliases'
+  - 'create article content'
+  - 'create page content'
+  - 'create terms in tags'
+  - 'create url aliases'
+  - 'delete article revisions'
+  - 'delete own article content'
+  - 'delete own page content'
+  - 'delete page revisions'
+  - 'edit own article content'
+  - 'edit own comments'
+  - 'edit own page content'
+  - 'edit terms in tags'
+  - 'revert all revisions'
+  - 'view all revisions'
+  - 'view own unpublished content'
+  - 'view the administration theme'

core/modules/help/tests/fixtures/update/help-topics-3087499.php

@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * @file
+ * Contains database additions for testing the upgrade path for help topics.
+ *
+ * @see https://www.drupal.org/node/3087499
+ */
+
+use Drupal\Core\Database\Database;
+use Drupal\Core\Serialization\Yaml;
+
+$connection = Database::getConnection();
+
+// Enable experimental help_topics module.
+$extensions = $connection->select('config')
+  ->fields('config', ['data'])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute()
+  ->fetchField();
+$extensions = unserialize($extensions);
+$extensions['module']['help_topics'] = 0;
+$connection->update('config')
+  ->fields([
+    'data' => serialize($extensions),
+  ])
+  ->condition('collection', '')
+  ->condition('name', 'core.extension')
+  ->execute();
+
+// Structure of configured block and search page.
+$search_page = Yaml::decode(file_get_contents(__DIR__ . '/search.page.help_search.yml'));
+$connection->insert('config')
+  ->fields([
+    'collection',
+    'name',
+    'data',
+  ])
+  ->values([
+    'collection' => '',
+    'name' => 'search.page.help_search',
+    'data' => serialize($search_page),
+  ])
+  ->execute();

core/modules/help/tests/fixtures/update/search.page.help_search.yml

@@ -0,0 +1,14 @@
+uuid: c0c6e5d5-c0b1-4874-8c94-ffed8929f5d7
+langcode: en
+status: true
+dependencies:
+  module:
+    - help_topics
+_core:
+  default_config_hash: RZ-bcSekNSsAbIPLW7Gmyd3uUjIOSrPvnb8RCCZYJm8
+id: help_search
+label: Help
+path: help
+weight: 0
+plugin: help_search
+configuration: {  }

core/modules/help/tests/modules/help_page_test/help_page_test.info.yml

@@ -0,0 +1,11 @@
+name: 'Help Page Test'
+type: module
+description: 'Module to test the help page.'
+package: Testing
+# version: VERSION
+hidden: true
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/help/tests/modules/help_page_test/help_page_test.module

@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Help Page Test module to test the help page.
+ */
+
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function help_page_test_help($route_name, RouteMatchInterface $route_match) {
+
+  switch ($route_name) {
+    case 'help.page.help_page_test':
+      // Make the help text conform to core standards. See
+      // \Drupal\system\Tests\Functional\GenericModuleTestBase::assertHookHelp().
+      return t('Read the <a href=":url">online documentation for the Help Page Test module</a>.', [':url' => 'http://www.example.com']);
+
+    case 'help_page_test.has_help':
+      return t('I have help!');
+
+    case 'help_page_test.test_array':
+      return ['#markup' => 'Help text from help_page_test_help module.'];
+  }
+
+  // Ensure that hook_help() can return an empty string and not cause the block
+  // to display.
+  return '';
+}

core/modules/help/tests/modules/help_page_test/help_page_test.routing.yml

@@ -0,0 +1,20 @@
+help_page_test.has_help:
+  path: '/help_page_test/has_help'
+  defaults:
+    _controller: '\Drupal\help_page_test\HelpPageTestController::hasHelp'
+  requirements:
+    _access: 'TRUE'
+
+help_page_test.no_help:
+  path: '/help_page_test/no_help'
+  defaults:
+    _controller: '\Drupal\help_page_test\HelpPageTestController::noHelp'
+  requirements:
+    _access: 'TRUE'
+
+help_page_test.test_array:
+  path: '/help_page_test/test_array'
+  defaults:
+    _controller: '\Drupal\help_page_test\HelpPageTestController::testArray'
+  requirements:
+    _access: 'TRUE'

core/modules/help/tests/modules/help_page_test/src/HelpPageTestController.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\help_page_test;
+
+/**
+ * Provides controllers for testing the help block.
+ */
+class HelpPageTestController {
+
+  /**
+   * Provides a route with help.
+   *
+   * @return array
+   *   A render array.
+   */
+  public function hasHelp() {
+    return ['#markup' => 'A route with help.'];
+  }
+
+  /**
+   * Provides a route with no help.
+   *
+   * @return array
+   *   A render array.
+   */
+  public function noHelp() {
+    return ['#markup' => 'A route without help.'];
+  }
+
+  /**
+   * Provides a route which has multiple array returns from hook_help().
+   *
+   * @return array
+   *   A render array.
+   */
+  public function testArray() {
+    return ['#markup' => 'A route which has multiple array returns from hook_help().'];
+  }
+
+}

core/modules/help/tests/modules/help_page_test/src/Plugin/HelpSection/EmptyHelpSection.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\help_page_test\Plugin\HelpSection;
+
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\help\Plugin\HelpSection\HelpSectionPluginBase;
+use Drupal\help\Attribute\HelpSection;
+
+/**
+ * Provides an empty section for the help page, for testing.
+ */
+#[HelpSection(
+  id: 'empty_section',
+  title: new TranslatableMarkup('Empty section'),
+  description: new TranslatableMarkup('This description should appear.')
+)]
+class EmptyHelpSection extends HelpSectionPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function listTopics() {
+    return [];
+  }
+
+}

core/modules/help/tests/modules/help_test/help_test.info.yml

@@ -0,0 +1,10 @@
+name: help_test
+type: module
+package: Testing
+dependencies:
+  - drupal:help
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/help/tests/modules/help_test/help_test.module

@@ -0,0 +1,16 @@
+<?php
+
+/**
+ * @file
+ * Test Help module.
+ */
+
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function help_test_help($route_name, RouteMatchInterface $route_match) {
+  // Do not implement a module overview page to test an empty implementation.
+  // @see \Drupal\help\Tests\HelpTest
+}

core/modules/help/tests/modules/help_test/src/SupernovaGenerator.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Drupal\help_test;
+
+use Drupal\Core\Routing\UrlGeneratorInterface;
+use Symfony\Component\Routing\RequestContext;
+
+/**
+ * Implements a URL generator which always thrown an exception.
+ */
+class SupernovaGenerator implements UrlGeneratorInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setContext(RequestContext $context) {
+    throw new \Exception();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getContext(): RequestContext {
+    throw new \Exception();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH): string {
+    throw new \Exception();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getPathFromRoute($name, $parameters = []) {
+    throw new \Exception();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function generateFromRoute($name, $parameters = [], $options = [], $collect_bubbleable_metadata = FALSE) {
+    throw new \Exception();
+  }
+
+}

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.bad_html.html.twig

@@ -0,0 +1,5 @@
+---
+label: 'Help topic with bad HTML syntax'
+top_level: true
+---
+<p>{% trans %}Body goes here{% endtrans %}</h3>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.bad_html2.html.twig

@@ -0,0 +1,6 @@
+---
+label: 'Bad HTML syntax within trans section'
+top_level: true
+---
+<p>{% trans %}<a href="/foo">Text here{% endtrans %}</a></p>
+

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.bad_html3.html.twig

@@ -0,0 +1,5 @@
+---
+label: 'Unclosed HTML tag'
+top_level: true
+---
+<p>{% trans %}<a href="/foo">Text here{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.empty.html.twig

@@ -0,0 +1,4 @@
+---
+label: 'Help topic containing no body'
+top_level: true
+---

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.h1.html.twig

@@ -0,0 +1,5 @@
+---
+label: 'Help topic with H1 header'
+top_level: true
+---
+<h1>{% trans %}Body goes here{% endtrans %}</h1>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.hierarchy.html.twig

@@ -0,0 +1,5 @@
+---
+label: 'Help topic with h3 without an h2'
+top_level: true
+---
+<h3>{% trans %}Body goes here{% endtrans %}</h3>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.locale.html.twig

@@ -0,0 +1,5 @@
+---
+label: 'Help topic with locale-unsafe tag'
+top_level: true
+---
+<p>{% trans %}some translated text and a <script>alert('hello')</script>{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.related.html.twig

@@ -0,0 +1,7 @@
+---
+label: 'Help topic related to nonexistent topic'
+top_level: true
+related:
+  - this.is.not.a.valid.help_topic.id
+---
+<p>{% trans %}Body goes here{% trans %}</p>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.top_level.html.twig

@@ -0,0 +1,4 @@
+---
+label: 'Help topic not top level or related to top level'
+---
+<p>{% trans %}Body goes here{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.translated.html.twig

@@ -0,0 +1,6 @@
+---
+label: 'Help topic with untranslated text'
+top_level: true
+---
+<p>Body goes here</p>
+<p>{% trans %}some translated text too{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/bad_help_topics/syntax/bad_help_topics.url_func_used.html.twig

@@ -0,0 +1,9 @@
+---
+label: 'URL test topic that uses outdated url function'
+top_level: true
+---
+{% set link_uses_url_func = render_var(url('valid.route')) %}
+<p>{% trans %}This topic should be top-level. It is used to test URLs{% endtrans %}</p>
+<ul>
+  <li>{% trans %}Valid link, but generated with <code>url()</code> instead of <code>help_route_link()</code> or <code>help_topic_link()</code>: {{ link_uses_url_func }}{% endtrans %}</li>
+</ul>

core/modules/help/tests/modules/help_topics_test/help_topics/help_topics_test.additional.html.twig

@@ -0,0 +1,6 @@
+---
+label: 'Additional topic'
+related:
+  - help_topics_test.test
+---
+<p>{% trans %}This topic should get listed automatically on the Help test topic.{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/help_topics/help_topics_test.linked.html.twig

@@ -0,0 +1,4 @@
+---
+label: 'Linked topic'
+---
+<p>{% trans %}This topic is not supposed to be top-level.{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/help_topics/help_topics_test.test.html.twig

@@ -0,0 +1,11 @@
+---
+label: "ABC Help Test module"
+top_level: true
+related:
+  - help_topics_test.linked
+  - does_not_exist.and_no_error
+---
+{% set help_topic_link = render_var(help_topic_link('help_topics_test.test_urls')) %}
+<p>{% trans %}This is a test. It should link to the URL test topic {{ help_topic_link }}. Also there should be a related topic link below to the Help module topic page and the linked topic.{% endtrans %}</p>
+<p>{% trans %}Non-word-item to translate.{% endtrans %}</p>
+<p>{% trans %}Test translation.{% endtrans %}</p>

core/modules/help/tests/modules/help_topics_test/help_topics/help_topics_test.test_urls.html.twig

@@ -0,0 +1,19 @@
+---
+label: 'URL test topic'
+top_level: true
+---
+{% set non_route_link = render_var(help_route_link('not a route', 'not_a_real_route')) %}
+{% set missing_params_link = render_var(help_route_link('missing params', 'help_topics_test.test_route')) %}
+{% set invalid_params_link = render_var(help_route_link('invalid params', 'help_topics_test.test_route', {'int_param': 'not_an_int'})) %}
+{% set valid_link = render_var(help_route_link('valid link', 'help_topics_test.test_route', {'int_param': 2})) %}
+{% set topic_link = render_var(help_topic_link('help_topics_test.additional')) %}
+{% set not_a_topic = render_var(help_topic_link('not_a_topic')) %}
+<p>{% trans %}This topic should be top-level. It is used to test URLs{% endtrans %}</p>
+<ul>
+  <li>{% trans %}Should not be a link: {{ non_route_link }}{% endtrans %}</li>
+  <li>{% trans %}Should not be a link: {{ missing_params_link }}{% endtrans %}</li>
+  <li>{% trans %}Should not be a link: {{ invalid_params_link }}{% endtrans %}</li>
+  <li>{% trans %}Should be a link if user has access: {{ valid_link }}{% endtrans %}</li>
+  <li>{% trans %}Should be a link: {{ topic_link }}{% endtrans %}</li>
+  <li>{% trans %}Should not be a link: {{ not_a_topic }}{% endtrans %}</li>
+</ul>

core/modules/help/tests/modules/help_topics_test/help_topics_test.help_topics.yml

@@ -0,0 +1,9 @@
+help_topics_test_direct_yml:
+  class: 'Drupal\help_topics_test\Plugin\HelpTopic\TestHelpTopicPlugin'
+  top_level: true
+  related: {}
+  label: "Test direct yaml topic label"
+  body: "Test direct yaml body"
+
+help_topics_derivatives:
+  deriver: 'Drupal\help_topics_test\Plugin\Deriver\TestHelpTopicDeriver'

core/modules/help/tests/modules/help_topics_test/help_topics_test.info.yml

@@ -0,0 +1,13 @@
+# The name of this module is deliberately different from its machine
+# name to test the presented order of help topics.
+name: 'ABC Help Test'
+type: module
+description: 'Support module for help testing.'
+package: Testing
+dependencies:
+  - drupal:help
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/help/tests/modules/help_topics_test/help_topics_test.module

@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @file
+ * Test module for help.
+ */
+
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function help_topics_test_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    case 'help.page.help_topics_test':
+      return 'Some kind of non-empty output for testing';
+  }
+}
+
+/**
+ * Implements hook_help_topics_info_alter().
+ */
+function help_topics_test_help_topics_info_alter(array &$info) {
+  // To prevent false positive search results limit list to testing topis only.
+  $filter = fn(string $key) => str_starts_with($key, 'help_topics_test') || in_array($key, [
+    'help_topics_test_direct_yml',
+    'help_topics_derivatives:test_derived_topic',
+  ], TRUE);
+  $info = array_filter($info, $filter, ARRAY_FILTER_USE_KEY);
+  $info['help_topics_test.test']['top_level'] = \Drupal::state()->get('help_topics_test.test:top_level', TRUE);
+}

core/modules/help/tests/modules/help_topics_test/help_topics_test.permissions.yml

@@ -0,0 +1,2 @@
+access test help:
+  title: 'Access the test help section'

core/modules/help/tests/modules/help_topics_test/help_topics_test.routing.yml

@@ -0,0 +1,11 @@
+help_topics_test.test_route:
+  path: '/help_topics_test/{int_param<\d+>}'
+  defaults:
+    _controller: '\Drupal\help_topics_test\Controller\HelpTopicsTestController::testPage'
+    _title: 'Page for testing URLs in topics'
+  requirements:
+    _permission: 'access test help'
+  options:
+    parameters:
+      required_param:
+        type: int

core/modules/help/tests/modules/help_topics_test/src/Controller/HelpTopicsTestController.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Drupal\help_topics_test\Controller;
+
+use Drupal\Core\Controller\ControllerBase;
+
+/**
+ * Returns the response for help_topics_test routes.
+ */
+class HelpTopicsTestController extends ControllerBase {
+
+  /**
+   * Displays a dummy page for testing.
+   *
+   * @param int $int_param
+   *   Required parameter (ignored).
+   *
+   * @return array
+   *   Render array for the dummy page.
+   */
+  public function testPage(int $int_param) {
+    $build = [
+      '#markup' => 'You have reached the help topics test routing page.',
+    ];
+    return $build;
+  }
+
+}

core/modules/help/tests/modules/help_topics_test/src/Plugin/Deriver/TestHelpTopicDeriver.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace Drupal\help_topics_test\Plugin\Deriver;
+
+use Drupal\Component\Plugin\Derivative\DeriverInterface;
+
+/**
+ * A test discovery deriver for fake help topics.
+ */
+class TestHelpTopicDeriver implements DeriverInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDerivativeDefinitions($base_plugin_definition) {
+    $prefix = $base_plugin_definition['id'];
+    $id = 'test_derived_topic';
+    $plugin_id = $prefix . ':' . $id;
+    $definitions[$id] = [
+      'plugin_id' => $plugin_id,
+      'id' => $plugin_id,
+      'class' => 'Drupal\\help_topics_test\\Plugin\\HelpTopic\\TestHelpTopicPlugin',
+      'label' => 'Label for ' . $id,
+      'body' => 'Body for ' . $id,
+      'top_level' => TRUE,
+      'related' => [],
+      'provider' => 'help_topics_test',
+    ];
+    return $definitions;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDerivativeDefinition($derivative_id, $base_plugin_definition) {
+    return $base_plugin_definition;
+  }
+
+}

core/modules/help/tests/modules/help_topics_test/src/Plugin/HelpSection/TestHelpSection.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace Drupal\help_topics_test\Plugin\HelpSection;
+
+use Drupal\help\SearchableHelpInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Url;
+use Drupal\Core\Link;
+use Drupal\help\Plugin\HelpSection\HelpSectionPluginBase;
+use Drupal\help\Attribute\HelpSection;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+
+// cspell:ignore asdrsad barmm foomm sqruct wcsrefsdf sdeeeee
+
+/**
+ * Provides a searchable help section for testing.
+ */
+#[HelpSection(
+  id: 'help_topics_test',
+  title: new TranslatableMarkup('Test section'),
+  description: new TranslatableMarkup('For testing search'),
+  permission: 'access test help',
+  weight: 100
+)]
+class TestHelpSection extends HelpSectionPluginBase implements SearchableHelpInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function listTopics() {
+    return [
+      Link::fromTextAndUrl('Foo', Url::fromUri('https://foo.com')),
+      Link::fromTextAndUrl('Bar', Url::fromUri('https://bar.com')),
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function listSearchableTopics() {
+    return ['foo', 'bar'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function renderTopicForSearch($topic_id, LanguageInterface $language) {
+    switch ($topic_id) {
+      case 'foo':
+        if ($language->getId() == 'en') {
+          return [
+            'title' => 'Foo in English title wcsrefsdf',
+            'text' => 'Something about foo body not-a-word-english sqruct',
+            'url' => Url::fromUri('https://foo.com'),
+          ];
+        }
+        return [
+          'title' => 'Foomm Foreign heading',
+          'text' => 'Fake foreign foo text not-a-word-german asdrsad',
+          'url' => Url::fromUri('https://mm.foo.com'),
+        ];
+
+      case 'bar':
+        if ($language->getId() == 'en') {
+          return [
+            'title' => 'Bar in English',
+            'text' => 'Something about bar another-word-english asdrsad',
+            'url' => Url::fromUri('https://bar.com'),
+          ];
+        }
+        return [
+          'title' => \Drupal::state()->get('help_topics_test:translated_title', 'Barmm Foreign sdeeeee'),
+          'text' => 'Fake foreign barmm another-word-german sqruct',
+          'url' => Url::fromUri('https://mm.bar.com'),
+        ];
+
+      default:
+        throw new \InvalidArgumentException('Unexpected ID encountered');
+    }
+  }
+
+}

core/modules/help/tests/modules/help_topics_test/src/Plugin/HelpTopic/TestHelpTopicPlugin.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Drupal\help_topics_test\Plugin\HelpTopic;
+
+use Drupal\Core\Cache\Cache;
+use Drupal\help\HelpTopicPluginBase;
+
+/**
+ * A fake help topic plugin for testing.
+ */
+class TestHelpTopicPlugin extends HelpTopicPluginBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getBody() {
+    return [
+      '#type' => 'markup',
+      '#markup' => $this->pluginDefinition['body'],
+    ];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheContexts() {
+    return [];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheTags() {
+    return ['foobar'];
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheMaxAge() {
+    return Cache::PERMANENT;
+  }
+
+}

core/modules/help/tests/modules/help_topics_twig_tester/help_topics_twig_tester.info.yml

@@ -0,0 +1,11 @@
+name: 'Help Topics Twig Tester'
+type: module
+description: 'Support module for help testing.'
+package: Testing
+dependencies:
+  - drupal:help
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/help/tests/modules/help_topics_twig_tester/help_topics_twig_tester.services.yml

@@ -0,0 +1,6 @@
+services:
+  help_test_twig.extension:
+    class: Drupal\help_topics_twig_tester\HelpTestTwigExtension
+    arguments: []
+    tags:
+      - { name: twig.extension, priority: 500 }

core/modules/help/tests/modules/help_topics_twig_tester/src/HelpTestTwigExtension.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Drupal\help_topics_twig_tester;
+
+use Twig\Extension\AbstractExtension;
+
+/**
+ * Defines and registers Drupal Twig extensions for testing help topics.
+ */
+class HelpTestTwigExtension extends AbstractExtension {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getNodeVisitors() {
+    return [
+      new HelpTestTwigNodeVisitor(),
+    ];
+  }
+
+}

core/modules/help/tests/modules/help_topics_twig_tester/src/HelpTestTwigNodeVisitor.php

@@ -0,0 +1,180 @@
+<?php
+
+namespace Drupal\help_topics_twig_tester;
+
+use Drupal\Core\Template\TwigNodeTrans;
+use Twig\Environment;
+use Twig\Node\Node;
+use Twig\Node\PrintNode;
+use Twig\Node\SetNode;
+use Twig\Node\TextNode;
+use Twig\Node\Expression\AbstractExpression;
+use Twig\NodeVisitor\NodeVisitorInterface;
+
+/**
+ * Defines a Twig node visitor for testing help topics.
+ *
+ * See static::setStateValue() for information on the special processing
+ * this class can do.
+ */
+class HelpTestTwigNodeVisitor implements NodeVisitorInterface {
+
+  /**
+   * Delimiter placed around single translated chunks.
+   */
+  public const DELIMITER = 'Not Likely To Be Inside A Template';
+
+  /**
+   * Name used in \Drupal::state() for saving state information.
+   */
+  protected const STATE_NAME = 'help_test_twig_node_visitor';
+
+  /**
+   * {@inheritdoc}
+   */
+  public function enterNode(Node $node, Environment $env): Node {
+    return $node;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function leaveNode(Node $node, Environment $env): ?Node {
+    $processing = static::getState();
+    if (!$processing['manner']) {
+      return $node;
+    }
+
+    // For all special processing, we want to remove variables, set statements,
+    // and assorted Twig expression calls (if, do, etc.).
+    if ($node instanceof SetNode || $node instanceof PrintNode ||
+       $node instanceof AbstractExpression) {
+      return NULL;
+    }
+
+    if ($node instanceof TwigNodeTrans) {
+      // Count the number of translated chunks.
+      $this_chunk = $processing['chunk_count'] + 1;
+      static::setStateValue('chunk_count', $this_chunk);
+      if ($this_chunk > $processing['max_chunk']) {
+        static::setStateValue('max_chunk', $this_chunk);
+      }
+
+      if ($processing['manner'] == 'remove_translated') {
+        // Remove all translated text.
+        return NULL;
+      }
+      elseif ($processing['manner'] == 'replace_translated') {
+        // Replace with a dummy string.
+        $node = new TextNode('dummy', 0);
+      }
+      elseif ($processing['manner'] == 'translated_chunk') {
+        // Return the text only if it's the next chunk we're supposed to return.
+        // Add a wrapper, because non-translated nodes will still be returned.
+        if ($this_chunk == $processing['return_chunk']) {
+          return new TextNode(static::DELIMITER . $this->extractText($node) . static::DELIMITER, 0);
+        }
+        else {
+          return NULL;
+        }
+      }
+    }
+
+    if ($processing['manner'] == 'remove_translated' && $node instanceof TextNode) {
+      // For this processing, we also want to remove all HTML tags and
+      // whitespace from TextNodes.
+      $text = $node->getAttribute('data');
+      $text = strip_tags($text);
+      $text = preg_replace('|\s+|', '', $text);
+      return new TextNode($text, 0);
+    }
+
+    return $node;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getPriority() {
+    return -100;
+  }
+
+  /**
+   * Extracts the text from a translated text object.
+   *
+   * @param \Drupal\Core\Template\TwigNodeTrans $node
+   *   Translated text node.
+   *
+   * @return string
+   *   Text in the node.
+   */
+  protected function extractText(TwigNodeTrans $node) {
+    // Extract the singular/body and optional plural text from the
+    // TwigNodeTrans object.
+    $bodies = $node->getNode('body');
+    if (!count($bodies)) {
+      $bodies = [$bodies];
+    }
+    if ($node->hasNode('plural')) {
+      $plural = $node->getNode('plural');
+      if (!count($plural)) {
+        $bodies[] = $plural;
+      }
+      else {
+        foreach ($plural as $item) {
+          $bodies[] = $item;
+        }
+      }
+    }
+
+    // Extract the text from each component of the singular/plural strings.
+    $text = '';
+    foreach ($bodies as $body) {
+      if ($body->hasAttribute('data')) {
+        $text .= $body->getAttribute('data');
+      }
+    }
+    return trim($text);
+  }
+
+  /**
+   * Returns the state information.
+   *
+   * @return array
+   *   The state information.
+   */
+  public static function getState() {
+    return \Drupal::state()->get(static::STATE_NAME, ['manner' => 0]);
+  }
+
+  /**
+   * Sets state information.
+   *
+   * @param string $key
+   *   Key to set. Possible keys:
+   *   - manner: Type of special processing to do when rendering. Values:
+   *     - 0: No processing.
+   *     - remove_translated: Remove all translated text, HTML tags, and
+   *       whitespace.
+   *     - replace_translated: Replace all translated text with dummy text.
+   *     - translated_chunk: Remove all translated text except one designated
+   *       chunk (see return_chunk below).
+   *     - bare_body (or any other non-zero value): Remove variables, set
+   *       statements, and Twig programming, but leave everything else intact.
+   *   - chunk_count: Current index of translated chunks. Reset to -1 before
+   *     each rendering run. (Used internally by this class.)
+   *   - max_chunk: Maximum index of translated chunks. Reset to -1 before
+   *     each rendering run.
+   *   - return_chunk: Chunk index to keep intact for translated_chunk
+   *     processing. All others are removed.
+   * @param $value
+   *   Value to set for $key.
+   */
+  public static function setStateValue(string $key, $value) {
+    $state = \Drupal::state();
+    $values = $state->get(static::STATE_NAME, ['manner' => 0]);
+    $values[$key] = $value;
+    $state->set(static::STATE_NAME, $values);
+  }
+
+}

core/modules/help/tests/modules/more_help_page_test/more_help_page_test.info.yml

@@ -0,0 +1,11 @@
+name: 'More Help Page Test'
+type: module
+description: 'Module to test the help page.'
+package: Testing
+# version: VERSION
+hidden: true
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222

core/modules/help/tests/modules/more_help_page_test/more_help_page_test.module

@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @file
+ * More Help Page Test module to test the help blocks.
+ */
+
+use Drupal\Core\Routing\RouteMatchInterface;
+
+/**
+ * Implements hook_help().
+ */
+function more_help_page_test_help($route_name, RouteMatchInterface $route_match) {
+
+  switch ($route_name) {
+    // Return help for the same route as the help_page_test module.
+    case 'help_page_test.test_array':
+      return ['#markup' => 'Help text from more_help_page_test_help module.'];
+  }
+}
+
+/**
+ * Implements hook_help_section_info_alter().
+ */
+function more_help_page_test_help_section_info_alter(array &$info) {
+  $info['hook_help']['weight'] = 500;
+}

core/modules/help/tests/src/Functional/AddPermissionsUpdateTest.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+use Drupal\user\Entity\Role;
+
+/**
+ * Tests help_post_update_add_permissions_to_roles().
+ *
+ * @group help
+ * @group legacy
+ * @group #slow
+ *
+ * @see help_post_update_add_permissions_to_roles()
+ */
+class AddPermissionsUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles(): void {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../system/tests/fixtures/update/drupal-9.4.0.filled.standard.php.gz',
+      __DIR__ . '/../../fixtures/update/drupal-10.access-help-pages.php',
+    ];
+  }
+
+  /**
+   * Tests adding 'access help pages' permission.
+   */
+  public function testUpdate(): void {
+    $roles = Role::loadMultiple();
+    $this->assertGreaterThan(2, count($roles));
+    foreach ($roles as $role) {
+      $permissions = $role->toArray()['permissions'];
+      $this->assertNotContains('access help pages', $permissions);
+    }
+
+    $this->runUpdates();
+
+    $role = Role::load(Role::ANONYMOUS_ID);
+    $permissions = $role->toArray()['permissions'];
+    $this->assertNotContains('access help pages', $permissions);
+
+    $role = Role::load(Role::AUTHENTICATED_ID);
+    $permissions = $role->toArray()['permissions'];
+    $this->assertNotContains('access help pages', $permissions);
+
+    // Admin roles have the permission and do not need assigned.
+    $role = Role::load('administrator');
+    $permissions = $role->toArray()['permissions'];
+    $this->assertNotContains('access help pages', $permissions);
+
+    $role = Role::load('content_editor');
+    $permissions = $role->toArray()['permissions'];
+    $this->assertContains('access help pages', $permissions);
+  }
+
+}

core/modules/help/tests/src/Functional/ExperimentalHelpTest.php

@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Verifies help for experimental modules.
+ *
+ * @group help
+ */
+class ExperimentalHelpTest extends BrowserTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * The experimental_module_test module implements hook_help() and is in the
+   * Core (Experimental) package.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'help',
+    'experimental_module_test',
+    'help_page_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * The admin user.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    $this->adminUser = $this->drupalCreateUser(['access help pages']);
+  }
+
+  /**
+   * Verifies that a warning message is displayed for experimental modules.
+   */
+  public function testExperimentalHelp(): void {
+    $this->drupalLogin($this->adminUser);
+    $this->drupalGet('admin/help/experimental_module_test');
+    $this->assertSession()->statusMessageContains('This module is experimental.', 'warning');
+
+    // Regular modules should not display the message.
+    $this->drupalGet('admin/help/help_page_test');
+    $this->assertSession()->statusMessageNotContains('This module is experimental.');
+
+    // Ensure the actual help page is displayed to avoid a false positive.
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('online documentation for the Help Page Test module');
+  }
+
+}

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

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

core/modules/help/tests/src/Functional/HelpBlockTest.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests display of help block.
+ *
+ * @group help
+ */
+class HelpBlockTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'help',
+    'help_page_test',
+    'block',
+    'more_help_page_test',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * The help block instance.
+   *
+   * @var \Drupal\block\Entity\Block
+   */
+  protected $helpBlock;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    $this->helpBlock = $this->placeBlock('help_block');
+  }
+
+  /**
+   * Logs in users, tests help pages.
+   */
+  public function testHelp(): void {
+    $this->drupalGet('help_page_test/has_help');
+    $this->assertSession()->pageTextContains('I have help!');
+    $this->assertSession()->pageTextContains($this->helpBlock->label());
+
+    $this->drupalGet('help_page_test/no_help');
+    // The help block should not appear when there is no help.
+    $this->assertSession()->pageTextNotContains($this->helpBlock->label());
+
+    // Ensure that if two hook_help() implementations both return a render array
+    // the output is as expected.
+    $this->drupalGet('help_page_test/test_array');
+    $this->assertSession()->pageTextContains('Help text from more_help_page_test_help module.');
+    $this->assertSession()->pageTextContains('Help text from help_page_test_help module.');
+  }
+
+}

core/modules/help/tests/src/Functional/HelpPageOrderTest.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Verify the order of the help page.
+ *
+ * @group help
+ */
+class HelpPageOrderTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['help', 'help_page_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Strings to search for on admin/help, in order.
+   *
+   * @var string[]
+   */
+  protected $stringOrder = [
+    'Module overviews are provided',
+    'This description should appear',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // Create and log in user.
+    $account = $this->drupalCreateUser([
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+    ]);
+    $this->drupalLogin($account);
+  }
+
+  /**
+   * Tests the order of the help page.
+   */
+  public function testHelp(): void {
+    $pos = 0;
+    $this->drupalGet('admin/help');
+    $page_text = $this->getTextContent();
+    foreach ($this->stringOrder as $item) {
+      $new_pos = strpos($page_text, $item, $pos);
+      $this->assertGreaterThan($pos, $new_pos, "Order of $item is not correct on help page");
+      $pos = $new_pos;
+    }
+  }
+
+}

core/modules/help/tests/src/Functional/HelpPageReverseOrderTest.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+/**
+ * Verify the order of the help page with an alter hook.
+ *
+ * @group help
+ */
+class HelpPageReverseOrderTest extends HelpPageOrderTest {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['more_help_page_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Strings to search for on admin/help, in order.
+   *
+   * These are reversed, due to the alter hook.
+   *
+   * @var string[]
+   */
+  protected $stringOrder = [
+    'This description should appear',
+    'Module overviews are provided',
+  ];
+
+}

core/modules/help/tests/src/Functional/HelpTest.php

@@ -0,0 +1,196 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Verify help display and user access to help based on permissions.
+ *
+ * @group help
+ */
+class HelpTest extends BrowserTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * The help_test module implements hook_help() but does not provide a module
+   * overview page. The help_page_test module has a page section plugin that
+   * returns no links.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'block_content',
+    'breakpoint',
+    'editor',
+    'help',
+    'help_page_test',
+    'help_test',
+    'history',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'claro';
+
+  /**
+   * The admin user that will be created.
+   */
+  protected $adminUser;
+
+  /**
+   * The anonymous user that will be created.
+   */
+  protected $anyUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // Create users.
+    $this->adminUser = $this->drupalCreateUser([
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+    ]);
+    $this->anyUser = $this->drupalCreateUser([]);
+  }
+
+  /**
+   * Logs in users, tests help pages.
+   */
+  public function testHelp(): void {
+    // Log in the root user to ensure as many admin links appear as possible on
+    // the module overview pages.
+    $this->drupalLogin($this->drupalCreateUser([
+      'access help pages',
+      'access administration pages',
+    ]));
+    $this->verifyHelp();
+
+    // Log in the regular user.
+    $this->drupalLogin($this->anyUser);
+    $this->verifyHelp(403);
+
+    // Verify that introductory help text exists, goes for 100% module coverage.
+    $this->drupalLogin($this->adminUser);
+    $this->drupalGet('admin/help');
+    $this->assertSession()->responseContains('For more information, refer to the help listed on this page or to the <a href="https://www.drupal.org/documentation">online documentation</a> and <a href="https://www.drupal.org/support">support</a> pages at <a href="https://www.drupal.org">drupal.org</a>.');
+
+    // Verify that hook_help() section title and description appear.
+    $this->assertSession()->responseContains('<h2>Module overviews</h2>');
+    $this->assertSession()->responseContains('<p>Module overviews are provided by modules. Overviews available for your installed modules:</p>');
+
+    // Verify that an empty section is handled correctly.
+    $this->assertSession()->responseContains('<h2>Empty section</h2>');
+    $this->assertSession()->responseContains('<p>This description should appear.</p>');
+    $this->assertSession()->pageTextContains('There is currently nothing in this section.');
+
+    // Make sure links are properly added for modules implementing hook_help().
+    foreach ($this->getModuleList() as $module => $name) {
+      $this->assertSession()->linkExists($name, 0, new FormattableMarkup('Link properly added to @name (admin/help/@module)', ['@module' => $module, '@name' => $name]));
+    }
+
+    // Ensure a module which does not provide a module overview page is handled
+    // correctly.
+    $module_name = \Drupal::service('extension.list.module')->getName('help_test');
+    $this->clickLink($module_name);
+    $this->assertSession()->pageTextContains('No help is available for module ' . $module_name);
+
+    // Verify that the order of topics is alphabetical by displayed module
+    // name, by checking the order of some modules, including some that would
+    // have a different order if it was done by machine name instead.
+    $this->drupalGet('admin/help');
+    $page_text = $this->getTextContent();
+    $start = strpos($page_text, 'Module overviews');
+    $pos = $start;
+    $list = ['Block', 'Block Content', 'Breakpoint', 'History', 'Text Editor'];
+    foreach ($list as $name) {
+      $this->assertSession()->linkExists($name);
+      $new_pos = strpos($page_text, $name, $start);
+      $this->assertGreaterThan($pos, $new_pos, "Order of $name is not correct on page");
+      $pos = $new_pos;
+    }
+  }
+
+  /**
+   * Verifies the logged in user has access to the various help pages.
+   *
+   * @param int $response
+   *   (optional) An HTTP response code. Defaults to 200.
+   */
+  protected function verifyHelp($response = 200) {
+    $this->drupalGet('admin/index');
+    $this->assertSession()->statusCodeEquals($response);
+    if ($response == 200) {
+      $this->assertSession()->pageTextContains('This page shows you all available administration tasks for each module.');
+    }
+    else {
+      $this->assertSession()->pageTextNotContains('This page shows you all available administration tasks for each module.');
+    }
+
+    $module_list = \Drupal::service('extension.list.module');
+    foreach ($this->getModuleList() as $module => $name) {
+      // View module help page.
+      $this->drupalGet('admin/help/' . $module);
+      $this->assertSession()->statusCodeEquals($response);
+      if ($response == 200) {
+        $this->assertSession()->titleEquals("$name | Drupal");
+        $this->assertEquals($name, $this->cssSelect('h1.page-title')[0]->getText(), "$module heading was displayed");
+        $info = $module_list->getExtensionInfo($module);
+        $admin_tasks = \Drupal::service('system.module_admin_links_helper')->getModuleAdminLinks($module);
+        if ($module_permissions_link = \Drupal::service('user.module_permissions_link_helper')->getModulePermissionsLink($module, $info['name'])) {
+          $admin_tasks["user.admin_permissions.{$module}"] = $module_permissions_link;
+        }
+        if (!empty($admin_tasks)) {
+          $this->assertSession()->pageTextContains($name . ' administration pages');
+        }
+        foreach ($admin_tasks as $task) {
+          $this->assertSession()->linkExists($task['title']);
+          // Ensure there are no double escaped '&' or '<' characters.
+          $this->assertSession()->assertNoEscaped('&amp;');
+          $this->assertSession()->assertNoEscaped('&lt;');
+          // Ensure there are no escaped '<' characters.
+          $this->assertSession()->assertNoEscaped('<');
+        }
+        // Ensure there are no double escaped '&' or '<' characters.
+        $this->assertSession()->assertNoEscaped('&amp;');
+        $this->assertSession()->assertNoEscaped('&lt;');
+
+        // The help for CKEditor 5 intentionally has escaped '<' so leave this
+        // iteration before the assertion below.
+        if ($module === 'ckeditor5') {
+          continue;
+        }
+        // Ensure there are no escaped '<' characters.
+        $this->assertSession()->assertNoEscaped('<');
+      }
+    }
+  }
+
+  /**
+   * Gets the list of enabled modules that implement hook_help().
+   *
+   * @return array
+   *   A list of enabled modules.
+   */
+  protected function getModuleList() {
+    $modules = [];
+    $module_data = $this->container->get('extension.list.module')->getList();
+    \Drupal::moduleHandler()->invokeAllWith(
+      'help',
+      function (callable $hook, string $module) use (&$modules, $module_data) {
+        $modules[$module] = $module_data[$module]->info['name'];
+      }
+    );
+    return $modules;
+  }
+
+}

core/modules/help/tests/src/Functional/HelpTopicSearchTest.php

@@ -0,0 +1,312 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\Traits\Core\CronRunTrait;
+use Drupal\help\Plugin\Search\HelpSearch;
+
+// cspell:ignore asdrsad barmm foomm hilfetestmodul sdeeeee sqruct testen
+// cspell:ignore wcsrefsdf übersetzung
+
+/**
+ * Verifies help topic search.
+ *
+ * @group help
+ * @group #slow
+ */
+class HelpTopicSearchTest extends HelpTopicTranslatedTestBase {
+
+  use CronRunTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'search',
+    'locale',
+    'language',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // Log in.
+    $this->drupalLogin($this->createUser([
+      'access help pages',
+      'administer site configuration',
+      'view the administration theme',
+      'administer permissions',
+      'administer languages',
+      'administer search',
+      'access test help',
+      'search content',
+    ]));
+
+    // Add English language and set to default.
+    $this->drupalGet('admin/config/regional/language/add');
+    $this->submitForm([
+      'predefined_langcode' => 'en',
+    ], 'Add language');
+    $this->drupalGet('admin/config/regional/language');
+    $this->submitForm([
+      'site_default_language' => 'en',
+    ], 'Save configuration');
+    // When default language is changed, the container is rebuilt in the child
+    // site, so a rebuild in the main site is required to use the new container
+    // here.
+    $this->rebuildContainer();
+
+    // Before running cron, verify that a search returns no results and shows
+    // warning.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'not-a-word-english'], 'Search');
+    $this->assertSearchResultsCount(0);
+    $this->assertSession()->statusMessageContains('Help search is not fully indexed', 'warning');
+
+    // Run cron until the topics are fully indexed, with a limit of 100 runs
+    // to avoid infinite loops.
+    $num_runs = 100;
+    $plugin = HelpSearch::create($this->container, [], 'help_search', []);
+    do {
+      $this->cronRun();
+      $remaining = $plugin->indexStatus()['remaining'];
+    } while (--$num_runs && $remaining);
+    $this->assertNotEmpty($num_runs);
+    $this->assertEmpty($remaining);
+
+    // Visit the Search settings page and verify it says 100% indexed.
+    $this->drupalGet('admin/config/search/pages');
+    $this->assertSession()->pageTextContains('100% of the site has been indexed');
+    // Search and verify there is no warning.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'not-a-word-english'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $this->assertSession()->statusMessageNotContains('Help search is not fully indexed');
+  }
+
+  /**
+   * Tests help topic search.
+   */
+  public function testHelpSearch(): void {
+    $german = \Drupal::languageManager()->getLanguage('de');
+    $session = $this->assertSession();
+
+    // Verify that when we search in English for a word that is only in
+    // English text, we find the topic. Note that these "words" are provided
+    // by the topics that come from
+    // \Drupal\help_topics_test\Plugin\HelpSection\TestHelpSection.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'not-a-word-english'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Foo in English title wcsrefsdf');
+
+    // Same for German.
+    $this->drupalGet('search/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'not-a-word-german'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Foomm Foreign heading');
+
+    // Verify when we search in English for a word that only exists in German,
+    // we get no results.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'not-a-word-german'], 'Search');
+    $this->assertSearchResultsCount(0);
+    $session->pageTextContains('no results');
+
+    // Same for German.
+    $this->drupalGet('search/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'not-a-word-english'], 'Search');
+    $this->assertSearchResultsCount(0);
+    $session->pageTextContains('no results');
+
+    // Verify when we search in English for a word that exists in one topic
+    // in English and a different topic in German, we only get the one English
+    // topic.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'sqruct'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Foo in English title wcsrefsdf');
+
+    // Same for German.
+    $this->drupalGet('search/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'asdrsad'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Foomm Foreign heading');
+
+    // All of the above tests used the TestHelpSection plugin. Also verify
+    // that we can search for translated regular help topics, in both English
+    // and German.
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'non-word-item'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('ABC Help Test module');
+    // Click the link and verify we ended up on the topic page.
+    $this->clickLink('ABC Help Test module');
+    $session->pageTextContains('This is a test');
+
+    $this->drupalGet('search/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'non-word-german'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('ABC-Hilfetestmodul');
+    $this->clickLink('ABC-Hilfetestmodul');
+    $session->pageTextContains('Übersetzung testen.');
+
+    // Verify that we can search from the admin/help page.
+    $this->drupalGet('admin/help');
+    $session->pageTextContains('Search help');
+    $this->submitForm(['keys' => 'non-word-item'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('ABC Help Test module');
+
+    // Same for German.
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'non-word-german'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('ABC-Hilfetestmodul');
+
+    // Verify we can search for title text (other searches used text
+    // that was part of the body).
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'wcsrefsdf'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Foo in English title wcsrefsdf');
+
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'sdeeeee'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Barmm Foreign sdeeeee');
+
+    // Just changing the title and running cron is not enough to reindex so
+    // 'sdeeeee' still hits a match. The content is updated because the help
+    // topic is rendered each time.
+    \Drupal::state()->set('help_topics_test:translated_title', 'Updated translated title');
+    $this->cronRun();
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'sdeeeee'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Updated translated title');
+    // Searching for the updated test shouldn't produce a match.
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'translated title'], 'Search');
+    $this->assertSearchResultsCount(0);
+
+    // Clear the caches and re-run cron - this should re-index the help.
+    $this->rebuildAll();
+    $this->cronRun();
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'sdeeeee'], 'Search');
+    $this->assertSearchResultsCount(0);
+    $this->drupalGet('admin/help', ['language' => $german]);
+    $this->submitForm(['keys' => 'translated title'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('Updated translated title');
+
+    // Verify the cache tags and contexts.
+    $session->responseHeaderContains('X-Drupal-Cache-Tags', 'config:search.page.help_search');
+    $session->responseHeaderContains('X-Drupal-Cache-Tags', 'search_index:help_search');
+    $session->responseHeaderContains('X-Drupal-Cache-Contexts', 'user.permissions');
+    $session->responseHeaderContains('X-Drupal-Cache-Contexts', 'languages:language_interface');
+
+    // Log in as a user that does not have permission to see TestHelpSection
+    // items, and verify they can still search for help topics but not see these
+    // items.
+    $this->drupalLogin($this->createUser([
+      'access help pages',
+      'administer site configuration',
+      'view the administration theme',
+      'administer permissions',
+      'administer languages',
+      'administer search',
+      'search content',
+    ]));
+
+    $this->drupalGet('admin/help');
+    $session->pageTextContains('Search help');
+
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'non-word-item'], 'Search');
+    $this->assertSearchResultsCount(1);
+    $session->linkExists('ABC Help Test module');
+
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'not-a-word-english'], 'Search');
+    $this->assertSearchResultsCount(0);
+    $session->pageTextContains('no results');
+
+    // Uninstall the test module and verify its topics are immediately not
+    // searchable.
+    \Drupal::service('module_installer')->uninstall(['help_topics_test']);
+    $this->drupalGet('search/help');
+    $this->submitForm(['keys' => 'non-word-item'], 'Search');
+    $this->assertSearchResultsCount(0);
+  }
+
+  /**
+   * Tests uninstalling the help_topics module.
+   */
+  public function testUninstall(): void {
+    \Drupal::service('module_installer')->uninstall(['help_topics_test']);
+    // Ensure we can uninstall help_topics and use the help system without
+    // breaking.
+    $this->drupalLogin($this->createUser([
+      'administer modules',
+      'access help pages',
+    ]));
+    $edit = [];
+    $edit['uninstall[help]'] = TRUE;
+    $this->drupalGet('admin/modules/uninstall');
+    $this->submitForm($edit, 'Uninstall');
+    $this->submitForm([], 'Uninstall');
+    $this->assertSession()->statusMessageContains('The selected modules have been uninstalled.', 'status');
+    $this->drupalGet('admin/help');
+    $this->assertSession()->statusCodeEquals(404);
+  }
+
+  /**
+   * Tests uninstalling the search module.
+   */
+  public function testUninstallSearch(): void {
+    // Ensure we can uninstall search and use the help system without
+    // breaking.
+    $this->drupalLogin($this->createUser([
+      'administer modules',
+      'access help pages',
+    ]));
+    $edit = [];
+    $edit['uninstall[search]'] = TRUE;
+    $this->drupalGet('admin/modules/uninstall');
+    $this->submitForm($edit, 'Uninstall');
+    $this->submitForm([], 'Uninstall');
+    $this->assertSession()->statusMessageContains('The selected modules have been uninstalled.', 'status');
+    $this->drupalGet('admin/help');
+    $this->assertSession()->statusCodeEquals(200);
+
+    // Rebuild the container to reflect the latest changes.
+    $this->rebuildContainer();
+    $this->assertTrue(\Drupal::moduleHandler()->moduleExists('help'), 'The help module is still installed.');
+    $this->assertFalse(\Drupal::moduleHandler()->moduleExists('search'), 'The search module is uninstalled.');
+  }
+
+  /**
+   * Asserts that help search returned the expected number of results.
+   *
+   * @param int $count
+   *   The expected number of search results.
+   *
+   * @internal
+   */
+  protected function assertSearchResultsCount(int $count): void {
+    $this->assertSession()->elementsCount('css', '.help_search-results > li', $count);
+  }
+
+}

core/modules/help/tests/src/Functional/HelpTopicTest.php

@@ -0,0 +1,298 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+use Drupal\Tests\system\Functional\Menu\AssertBreadcrumbTrait;
+
+/**
+ * Verifies help topic display and user access to help based on permissions.
+ *
+ * @group help
+ */
+class HelpTopicTest extends BrowserTestBase {
+  use AssertBreadcrumbTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  protected static $modules = [
+    'help_topics_test',
+    'help',
+    'block',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * The admin user that will be created.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $adminUser;
+
+  /**
+   * The user who can see help but not the special route.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $noTestUser;
+
+  /**
+   * The anonymous user that will be created.
+   *
+   * @var \Drupal\user\UserInterface
+   */
+  protected $anyUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // These tests rely on some markup from the 'stark' theme and we test theme
+    // provided help topics.
+    \Drupal::service('theme_installer')->install(['help_topics_test_theme']);
+
+    // Place various blocks.
+    $settings = [
+      'theme' => 'stark',
+      'region' => 'help',
+    ];
+    $this->placeBlock('help_block', $settings);
+    $this->placeBlock('local_tasks_block', $settings);
+    $this->placeBlock('local_actions_block', $settings);
+    $this->placeBlock('page_title_block', $settings);
+    $this->placeBlock('system_breadcrumb_block', $settings);
+
+    // Create users.
+    $this->adminUser = $this->createUser([
+      'access administration pages',
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+      'administer site configuration',
+      'access test help',
+    ]);
+
+    $this->noTestUser = $this->createUser([
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+      'administer site configuration',
+    ]);
+
+    $this->anyUser = $this->createUser([]);
+  }
+
+  /**
+   * Tests the main help page and individual pages for topics.
+   */
+  public function testHelp(): void {
+    $session = $this->assertSession();
+
+    // Log in the regular user.
+    $this->drupalLogin($this->anyUser);
+    $this->verifyHelp(403);
+
+    // Log in the admin user.
+    $this->drupalLogin($this->adminUser);
+    $this->verifyHelp();
+    $this->verifyBreadCrumb();
+
+    // Verify that help topics text appears on admin/help, and cache tags.
+    $this->drupalGet('admin/help');
+    $session->responseContains('<h2>Topics</h2>');
+    $session->pageTextContains('Topics can be provided by modules or themes');
+    $session->responseHeaderContains('X-Drupal-Cache-Tags', 'core.extension');
+
+    // Verify links for help topics and order.
+    $page_text = $this->getTextContent();
+    $start = strpos($page_text, 'Topics can be provided');
+    $pos = $start;
+    foreach ($this->getTopicList() as $info) {
+      $name = $info['name'];
+      $session->linkExists($name);
+      $new_pos = strpos($page_text, $name, $start);
+      $this->assertGreaterThan($pos, $new_pos, "Order of $name is not correct on page");
+      $pos = $new_pos;
+    }
+
+    // Ensure the plugin manager alter hook works as expected.
+    $session->linkExists('ABC Help Test module');
+    \Drupal::state()->set('help_topics_test.test:top_level', FALSE);
+    \Drupal::service('plugin.manager.help_topic')->clearCachedDefinitions();
+    $this->drupalGet('admin/help');
+    $session->linkNotExists('ABC Help Test module');
+    \Drupal::state()->set('help_topics_test.test:top_level', TRUE);
+    \Drupal::service('plugin.manager.help_topic')->clearCachedDefinitions();
+    $this->drupalGet('admin/help');
+
+    // Ensure all the expected links are present before uninstalling.
+    $session->linkExists('ABC Help Test module');
+    $session->linkExists('ABC Help Test');
+    $session->linkExists('XYZ Help Test theme');
+
+    // Uninstall the test module and verify the topics are gone, after
+    // reloading page.
+    $this->container->get('module_installer')->uninstall(['help_topics_test']);
+    $this->drupalGet('admin/help');
+    $session->linkNotExists('ABC Help Test module');
+    $session->linkNotExists('ABC Help Test');
+    $session->linkExists('XYZ Help Test theme');
+
+    // Uninstall the test theme and verify the topic is gone.
+    $this->container->get('theme_installer')->uninstall(['help_topics_test_theme']);
+    $this->drupalGet('admin/help');
+    $session->linkNotExists('XYZ Help Test theme');
+  }
+
+  /**
+   * Verifies the logged in user has access to various help links and pages.
+   *
+   * @param int $response
+   *   (optional) The HTTP response code to test for. If it's 200 (default),
+   *   the test verifies the user sees the help; if it's not, it verifies they
+   *   are denied access.
+   */
+  protected function verifyHelp($response = 200) {
+    // Verify access to help topic pages.
+    foreach ($this->getTopicList() as $topic => $info) {
+      // View help topic page.
+      $this->drupalGet('admin/help/topic/' . $topic);
+      $session = $this->assertSession();
+      $session->statusCodeEquals($response);
+      if ($response == 200) {
+        // Verify page information.
+        $name = $info['name'];
+        $session->titleEquals($name . ' | Drupal');
+        $session->responseContains('<h1>' . $name . '</h1>');
+        foreach ($info['tags'] as $tag) {
+          $session->responseHeaderContains('X-Drupal-Cache-Tags', $tag);
+        }
+      }
+    }
+  }
+
+  /**
+   * Verifies links on various topic pages.
+   */
+  public function testHelpLinks(): void {
+    $session = $this->assertSession();
+    $this->drupalLogin($this->adminUser);
+
+    // Verify links on the test top-level page.
+    $page = 'admin/help/topic/help_topics_test.test';
+    // Array element is the page text if you click through.
+    $links = [
+      'Linked topic' => 'This topic is not supposed to be top-level',
+      'Additional topic' => 'This topic should get listed automatically',
+      'URL test topic' => 'It is used to test URLs',
+    ];
+    foreach ($links as $link_text => $page_text) {
+      $this->drupalGet($page);
+      $this->clickLink($link_text);
+      $session->pageTextContains($page_text);
+    }
+
+    // Verify theme provided help topics work and can be related.
+    $this->drupalGet('admin/help/topic/help_topics_test_theme.test');
+    $session->pageTextContains('This is a theme provided topic.');
+    $this->assertStringContainsString('This is a theme provided topic.', $session->elementExists('css', 'article')->getText());
+    $this->clickLink('Additional topic');
+    $session->linkExists('XYZ Help Test theme');
+
+    // Verify that the non-top-level topics do not appear on the Help page.
+    $this->drupalGet('admin/help');
+    $session->linkNotExists('Linked topic');
+    $session->linkNotExists('Additional topic');
+
+    // Verify links and non-links on the URL test page.
+    $this->drupalGet('admin/help/topic/help_topics_test.test_urls');
+    $links = [
+      'not a route' => FALSE,
+      'missing params' => FALSE,
+      'invalid params' => FALSE,
+      'valid link' => TRUE,
+      'Additional topic' => TRUE,
+      'Missing help topic not_a_topic' => FALSE,
+    ];
+    foreach ($links as $text => $should_be_link) {
+      if ($should_be_link) {
+        $session->linkExists($text);
+      }
+      else {
+        // Should be text that is not a link.
+        $session->pageTextContains($text);
+        $session->linkNotExists($text);
+      }
+    }
+
+    // Verify that the "no test" user, who should not be able to access
+    // the 'valid link' URL, sees it as not a link.
+    $this->drupalLogin($this->noTestUser);
+    $this->drupalGet('admin/help/topic/help_topics_test.test_urls');
+    $session->pageTextContains('valid link');
+    $session->linkNotExists('valid link');
+  }
+
+  /**
+   * Gets a list of topic IDs to test.
+   *
+   * @return array
+   *   A list of topics to test, in the order in which they should appear. The
+   *   keys are the machine names of the topics. The values are arrays with the
+   *   following elements:
+   *   - name: Displayed name.
+   *   - tags: Cache tags to test for.
+   */
+  protected function getTopicList() {
+    return [
+      'help_topics_test.test' => [
+        'name' => 'ABC Help Test module',
+        'tags' => ['core.extension'],
+      ],
+      'help_topics_derivatives:test_derived_topic' => [
+        'name' => 'Label for test_derived_topic',
+        'tags' => ['foobar'],
+      ],
+      'help_topics_test_direct_yml' => [
+        'name' => 'Test direct yaml topic label',
+        'tags' => ['foobar'],
+      ],
+    ];
+  }
+
+  /**
+   * Tests breadcrumb on a help topic page.
+   */
+  public function verifyBreadCrumb() {
+    // Verify Help Topics administration breadcrumbs.
+    $trail = [
+      '' => 'Home',
+      'admin' => 'Administration',
+      'admin/help' => 'Help',
+    ];
+    $this->assertBreadcrumb('admin/help/topic/help_topics_test.test', $trail);
+    // Ensure we are on the expected help topic page.
+    $this->assertSession()->pageTextContains('Also there should be a related topic link below to the Help module topic page and the linked topic.');
+
+    // Verify that another page does not have the help breadcrumb.
+    $trail = [
+      '' => 'Home',
+      'admin' => 'Administration',
+      'admin/config' => 'Configuration',
+      'admin/config/system' => 'System',
+    ];
+    $this->assertBreadcrumb('admin/config/system/site-information', $trail);
+  }
+
+}

core/modules/help/tests/src/Functional/HelpTopicTranslatedTestBase.php

@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+// cspell:ignore hilfetestmodul übersetzung
+
+/**
+ * Provides a base class for functional help topic tests that use translation.
+ *
+ * Installs in German, with a small PO file, and sets up the task, help, and
+ * page title blocks.
+ */
+abstract class HelpTopicTranslatedTestBase extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'help_topics_test',
+    'help',
+    'block',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // These tests rely on some markup from the 'Claro' theme, as well as an
+    // optional block added when Claro is enabled.
+    \Drupal::service('theme_installer')->install(['claro']);
+    \Drupal::configFactory()->getEditable('system.theme')
+      ->set('admin', 'claro')
+      ->save(TRUE);
+
+    // Place various blocks.
+    $settings = [
+      'theme' => 'claro',
+      'region' => 'help',
+    ];
+    $this->placeBlock('help_block', $settings);
+    $this->placeBlock('local_tasks_block', $settings);
+    $this->placeBlock('local_actions_block', $settings);
+    $this->placeBlock('page_title_block', $settings);
+
+    // Create user.
+    $this->drupalLogin($this->createUser([
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+    ]));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function installParameters() {
+    $parameters = parent::installParameters();
+    // Install in German. This will ensure the language and locale modules are
+    // installed.
+    $parameters['parameters']['langcode'] = 'de';
+    // Create a po file so we don't attempt to download one from
+    // localize.drupal.org and to have a test translation that will not change.
+    \Drupal::service('file_system')->mkdir($this->publicFilesDirectory . '/translations', NULL, TRUE);
+    $contents = <<<PO
+msgid ""
+msgstr ""
+
+msgid "ABC Help Test module"
+msgstr "ABC-Hilfetestmodul"
+
+msgid "Test translation."
+msgstr "Übersetzung testen."
+
+msgid "Non-word-item to translate."
+msgstr "Non-word-german sdfwedrsdf."
+
+PO;
+    $version = explode('.', \Drupal::VERSION)[0] . '.0.0';
+    file_put_contents($this->publicFilesDirectory . "/translations/drupal-{$version}.de.po", $contents);
+    return $parameters;
+  }
+
+}

core/modules/help/tests/src/Functional/HelpTopicTranslationTest.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+// cspell:ignore hilfetestmodul testen übersetzung
+
+/**
+ * Verifies help topic translations.
+ *
+ * @group help
+ */
+class HelpTopicTranslationTest extends HelpTopicTranslatedTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // Create user and log in.
+    $this->drupalLogin($this->createUser([
+      'access help pages',
+      'view the administration theme',
+      'administer permissions',
+    ]));
+  }
+
+  /**
+   * Tests help topic translations.
+   */
+  public function testHelpTopicTranslations(): void {
+    $session = $this->assertSession();
+
+    // Verify that help topic link is translated on admin/help.
+    $this->drupalGet('admin/help');
+    $session->linkExists('ABC-Hilfetestmodul');
+    // Verify that the language cache tag appears on admin/help.
+    $session->responseHeaderContains('X-Drupal-Cache-Contexts', 'languages:language_interface');
+    // Verify that help topic is translated.
+    $this->drupalGet('admin/help/topic/help_topics_test.test');
+    $session->pageTextContains('ABC-Hilfetestmodul');
+    $session->pageTextContains('Übersetzung testen.');
+    // Verify that the language cache tag appears on a topic page.
+    $session->responseHeaderContains('X-Drupal-Cache-Contexts', 'languages:language_interface');
+  }
+
+}

core/modules/help/tests/src/Functional/HelpTopicsSyntaxTest.php

@@ -0,0 +1,353 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Core\Extension\ExtensionLifecycle;
+use Drupal\Component\FrontMatter\FrontMatter;
+use Drupal\Tests\BrowserTestBase;
+use Drupal\help\HelpTopicDiscovery;
+use Drupal\help_topics_twig_tester\HelpTestTwigNodeVisitor;
+use PHPUnit\Framework\ExpectationFailedException;
+use PHPUnit\Framework\AssertionFailedError;
+
+/**
+ * Verifies that all core Help topics can be rendered and comply with standards.
+ *
+ * @group help
+ * @group #slow
+ */
+class HelpTopicsSyntaxTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'help',
+    'help_topics_twig_tester',
+    'locale',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * Tests that all Core help topics can be rendered and have good syntax.
+   */
+  public function testHelpTopics(): void {
+    $this->drupalLogin($this->createUser([
+      'administer modules',
+      'access help pages',
+    ]));
+
+    // Enable all modules and themes, so that all routes mentioned in topics
+    // will be defined.
+    $module_directories = $this->listDirectories('module');
+    $modules_to_install = array_keys($module_directories);
+    \Drupal::service('module_installer')->install($modules_to_install);
+    $theme_directories = $this->listDirectories('theme');
+    \Drupal::service('theme_installer')->install(array_keys($theme_directories));
+
+    $directories = $module_directories + $theme_directories +
+      $this->listDirectories('profile');
+    $directories['core'] = \Drupal::root() . '/core/help_topics';
+    $directories['bad_help_topics'] = \Drupal::service('extension.list.module')->getPath('help_topics_test') . '/bad_help_topics/syntax/';
+
+    // Filter out directories outside of core. If you want to run this test
+    // on a contrib/custom module, remove the next line.
+    $directories = array_filter($directories, function ($directory) {
+      return str_starts_with($directory, 'core');
+    });
+
+    // Verify that a few key modules, themes, and profiles are listed, so that
+    // we can be certain our directory list is complete and we will be testing
+    // all existing help topics. If these lines in the test fail in the future,
+    // it is probably because something we chose to list here is being removed.
+    // Substitute another item of the same type that still exists, so that this
+    // test can continue.
+    $this->assertArrayHasKey('system', $directories, 'System module is being scanned');
+    $this->assertArrayHasKey('help', $directories, 'Help module is being scanned');
+    $this->assertArrayHasKey('claro', $directories, 'Claro theme is being scanned');
+    $this->assertArrayHasKey('standard', $directories, 'Standard profile is being scanned');
+
+    $definitions = (new HelpTopicDiscovery($directories))->getDefinitions();
+    $this->assertGreaterThan(0, count($definitions), 'At least 1 topic was found');
+
+    // Test each topic for compliance with standards, or for failing in the
+    // right way.
+    foreach (array_keys($definitions) as $id) {
+      if (str_starts_with($id, 'bad_help_topics.')) {
+        $this->verifyBadTopic($id, $definitions);
+      }
+      else {
+        $this->verifyTopic($id, $definitions);
+      }
+    }
+  }
+
+  /**
+   * Verifies rendering and standards compliance of one help topic.
+   *
+   * @param string $id
+   *   ID of the topic to verify.
+   * @param array $definitions
+   *   Array of all topic definitions, keyed by ID.
+   * @param int $response
+   *   Expected response from visiting the page for the topic.
+   */
+  protected function verifyTopic($id, $definitions, $response = 200) {
+    $definition = $definitions[$id];
+    HelpTestTwigNodeVisitor::setStateValue('manner', 0);
+
+    // Visit the URL for the topic.
+    $this->drupalGet('admin/help/topic/' . $id);
+
+    // Verify the title and response.
+    $session = $this->assertSession();
+    $session->statusCodeEquals($response);
+    if ($response == 200) {
+      $session->titleEquals($definition['label'] . ' | Drupal');
+    }
+
+    // Verify that all the related topics exist. Also check to see if any of
+    // them are top-level (we will need that in the next section).
+    $has_top_level_related = FALSE;
+    if (isset($definition['related'])) {
+      foreach ($definition['related'] as $related_id) {
+        $this->assertArrayHasKey($related_id, $definitions, 'Topic ' . $id . ' is only related to topics that exist: ' . $related_id);
+        $has_top_level_related = $has_top_level_related || !empty($definitions[$related_id]['top_level']);
+      }
+    }
+
+    // Verify this is either top-level or related to a top-level topic.
+    $this->assertTrue(!empty($definition['top_level']) || $has_top_level_related, 'Topic ' . $id . ' is either top-level or related to at least one other top-level topic');
+
+    // Verify that the label is not empty.
+    $this->assertNotEmpty($definition['label'], 'Topic ' . $id . ' has a non-empty label');
+
+    // Test the syntax and contents of the Twig file (without the front
+    // matter, which is tested in other ways above). We need to render the
+    // template several times with variations, so read it in once.
+    $template = file_get_contents($definition[HelpTopicDiscovery::FILE_KEY]);
+    $template_text = FrontMatter::create($template)->getContent();
+
+    // Verify that the body is not empty and is valid HTML.
+    $text = $this->renderHelpTopic($template_text, 'bare_body');
+    $this->assertNotEmpty($text, 'Topic ' . $id . ' contains some text outside of front matter');
+    $this->validateHtml($text, $id);
+    $max_chunk_num = HelpTestTwigNodeVisitor::getState()['max_chunk'];
+    $this->assertTrue($max_chunk_num >= 0, 'Topic ' . $id . ' has at least one translated chunk');
+
+    // Verify that each chunk of the translated text is locale-safe and
+    // valid HTML.
+    $chunk_num = 0;
+    $number_checked = 0;
+    while ($chunk_num <= $max_chunk_num) {
+      $chunk_str = $id . ' section ' . $chunk_num;
+
+      // Render the topic, asking for just one chunk, and extract the chunk.
+      // Note that some chunks may not actually get rendered, if they are inside
+      // set statements, because we skip rendering variable output.
+      HelpTestTwigNodeVisitor::setStateValue('return_chunk', $chunk_num);
+      $text = $this->renderHelpTopic($template_text, 'translated_chunk');
+      $matches = [];
+      $matched = preg_match('|' . HelpTestTwigNodeVisitor::DELIMITER . '(.*)' . HelpTestTwigNodeVisitor::DELIMITER . '|', $text, $matches);
+      if ($matched) {
+        $number_checked++;
+        $text = $matches[1];
+        $this->assertNotEmpty($text, 'Topic ' . $chunk_str . ' contains text');
+
+        // Verify the chunk is OK.
+        $this->assertTrue(locale_string_is_safe($text), 'Topic ' . $chunk_str . ' translatable string is locale-safe');
+        $this->validateHtml($text, $chunk_str);
+      }
+      $chunk_num++;
+    }
+    $this->assertTrue($number_checked > 0, 'Tested at least one translated chunk in ' . $id);
+
+    // Validate the HTML in the body with the translated text replaced by a
+    // dummy string, to verify that HTML syntax is not partly in and partly out
+    // of the translated text.
+    $text = $this->renderHelpTopic($template_text, 'replace_translated');
+    $this->validateHtml($text, $id);
+
+    // Verify that if we remove all the translated text, whitespace, and
+    // HTML tags, there is nothing left (that is, all text is translated).
+    $text = preg_replace('|\s+|', '', $this->renderHelpTopic($template_text, 'remove_translated'));
+    $this->assertEmpty($text, 'Topic ' . $id . ' Twig file has all of its text translated');
+
+    // Verify that the Twig url() function was not used.
+    $this->assertStringNotContainsString('url(', $template, 'Topic ' . $id . ' appears to use the url() function. Replace with help_topic_link() or help_topic_route(). See https://drupal.org/node/3074421');
+  }
+
+  /**
+   * Validates the HTML and header hierarchy for topic text.
+   *
+   * @param string $body
+   *   Body text to validate.
+   * @param string $id
+   *   ID of help topic (for error messages).
+   */
+  protected function validateHtml(string $body, string $id) {
+    $doc = new \DOMDocument();
+    $doc->strictErrorChecking = TRUE;
+    $doc->validateOnParse = FALSE;
+    libxml_use_internal_errors(TRUE);
+    if (!$doc->loadXML('<html><body>' . $body . '</body></html>')) {
+      foreach (libxml_get_errors() as $error) {
+        $this->fail('Topic ' . $id . ' fails HTML validation: ' . $error->message);
+      }
+
+      libxml_clear_errors();
+    }
+
+    // Check for headings hierarchy.
+    $levels = [1, 2, 3, 4, 5, 6];
+    foreach ($levels as $level) {
+      $num_headings[$level] = $doc->getElementsByTagName('h' . $level)->length;
+      if ($level == 1) {
+        $this->assertSame(0, $num_headings[1], 'Topic ' . $id . ' has no H1 tag');
+        // Set num_headings to 1 for this level, so the rest of the hierarchy
+        // can be tested using simpler code.
+        $num_headings[1] = 1;
+      }
+      else {
+        // We should either not have this heading, or if we do have one at this
+        // level, we should also have the next-smaller level. That is, if we
+        // have an h3, we should have also had an h2.
+        $this->assertTrue($num_headings[$level - 1] > 0 || $num_headings[$level] == 0,
+          'Topic ' . $id . ' has the correct H2-H6 heading hierarchy');
+      }
+    }
+  }
+
+  /**
+   * Verifies that a bad topic fails in the expected way.
+   *
+   * @param string $id
+   *   ID of the topic to verify. It should start with "bad_help_topics.".
+   * @param array $definitions
+   *   Array of all topic definitions, keyed by ID.
+   */
+  protected function verifyBadTopic($id, $definitions) {
+    $bad_topic_type = substr($id, 16);
+    // Topics should fail verifyTopic() in specific ways.
+    $found_error = FALSE;
+    try {
+      $this->verifyTopic($id, $definitions, 404);
+    }
+    catch (ExpectationFailedException | AssertionFailedError $e) {
+      $found_error = TRUE;
+      $message = $e->getMessage();
+      switch ($bad_topic_type) {
+        case 'related':
+          $this->assertStringContainsString('only related to topics that exist', $message);
+          break;
+
+        case 'bad_html':
+        case 'bad_html2':
+        case 'bad_html3':
+          $this->assertStringContainsString('Opening and ending tag mismatch', $message);
+          break;
+
+        case 'top_level':
+          $this->assertStringContainsString('is either top-level or related to at least one other top-level topic', $message);
+          break;
+
+        case 'empty':
+          $this->assertStringContainsString('contains some text outside of front matter', $message);
+          break;
+
+        case 'translated':
+          $this->assertStringContainsString('Twig file has all of its text translated', $message);
+          break;
+
+        case 'locale':
+          $this->assertStringContainsString('translatable string is locale-safe', $message);
+          break;
+
+        case 'h1':
+          $this->assertStringContainsString('has no H1 tag', $message);
+          break;
+
+        case 'hierarchy':
+          $this->assertStringContainsString('has the correct H2-H6 heading hierarchy', $message);
+          break;
+
+        case 'url_func_used':
+          $this->assertStringContainsString('appears to use the url() function', $message);
+          break;
+
+        default:
+          // This was an unexpected error.
+          throw $e;
+      }
+    }
+
+    if (!$found_error) {
+      $this->fail('Bad help topic ' . $bad_topic_type . ' did not fail as expected');
+    }
+  }
+
+  /**
+   * Lists the extension help topic directories of a certain type.
+   *
+   * @param string $type
+   *   The type of extension to list: module, theme, or profile.
+   *
+   * @return string[]
+   *   An array of all of the help topic directories for this type of
+   *   extension, keyed by extension short name.
+   */
+  protected function listDirectories($type) {
+    $directories = [];
+
+    // Find the extensions of this type, even if they are not installed, but
+    // excluding test ones.
+    $lister = \Drupal::service('extension.list.' . $type);
+    foreach ($lister->getAllAvailableInfo() as $name => $info) {
+      // Skip obsolete and deprecated modules.
+      if ($info[ExtensionLifecycle::LIFECYCLE_IDENTIFIER] === ExtensionLifecycle::OBSOLETE || $info[ExtensionLifecycle::LIFECYCLE_IDENTIFIER] === ExtensionLifecycle::DEPRECATED) {
+        continue;
+      }
+      $path = $lister->getPath($name);
+      // You can tell test modules because they are in package 'Testing', but
+      // test themes are only known by being found in test directories. So...
+      // exclude things in test directories.
+      if (!str_contains($path, '/tests') && !str_contains($path, '/testing')) {
+        $directories[$name] = $path . '/help_topics';
+      }
+    }
+    return $directories;
+  }
+
+  /**
+   * Renders a help topic in a special manner.
+   *
+   * @param string $content
+   *   Template text, without the front matter.
+   * @param string $manner
+   *   The special processing choice for topic rendering.
+   *
+   * @return string
+   *   The rendered topic.
+   */
+  protected function renderHelpTopic(string $content, string $manner) {
+    // Set up the special state variables for rendering.
+    HelpTestTwigNodeVisitor::setStateValue('manner', $manner);
+    HelpTestTwigNodeVisitor::setStateValue('max_chunk', -1);
+    HelpTestTwigNodeVisitor::setStateValue('chunk_count', -1);
+
+    // Add a random comment to the end, to thwart caching, and render. We need
+    // the HelpTestTwigNodeVisitor class to hit it each time we render.
+    $build = [
+      '#type' => 'inline_template',
+      '#template' => $content . "\n{# " . rand() . " #}",
+    ];
+    return (string) \Drupal::service('renderer')->renderInIsolation($build);
+  }
+
+}

core/modules/help/tests/src/Functional/NoHelpTest.php

@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Verify no help is displayed for modules not providing any help.
+ *
+ * @group help
+ */
+class NoHelpTest extends BrowserTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * Use one of the test modules that do not implement hook_help().
+   *
+   * @var array
+   */
+  protected static $modules = ['help', 'menu_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * The user who will be created.
+   */
+  protected $adminUser;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+    $this->adminUser = $this->drupalCreateUser(['access help pages']);
+  }
+
+  /**
+   * Ensures modules not implementing help do not appear on admin/help.
+   */
+  public function testMainPageNoHelp(): void {
+    $this->drupalLogin($this->adminUser);
+
+    $this->drupalGet('admin/help');
+    $this->assertSession()->statusCodeEquals(200);
+    $this->assertSession()->pageTextContains('Module overviews are provided by modules');
+    $this->assertFalse(\Drupal::moduleHandler()->hasImplementations('help', 'menu_test'), 'The menu_test module does not implement hook_help');
+    // Make sure the test module menu_test does not display a help link on
+    // admin/help.
+    $this->assertSession()->pageTextNotContains(\Drupal::service('extension.list.module')->getName('menu_test'));
+
+    // Ensure that the module overview help page for a module that does not
+    // implement hook_help() results in a 404.
+    $this->drupalGet('admin/help/menu_test');
+    $this->assertSession()->statusCodeEquals(404);
+  }
+
+}

core/modules/help/tests/src/Functional/Update/HelpTopicsMerge.php

@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional\Update;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+use Drupal\block\Entity\Block;
+use Drupal\search\Entity\SearchPage;
+
+/**
+ * Tests merging help topics module when the module is not installed.
+ *
+ * @group Update
+ * @group #slow
+ */
+class HelpTopicsMerge extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-9.4.0.bare.standard.php.gz',
+    ];
+  }
+
+  /**
+   * Tests upgrading help module for help topics.
+   *
+   * @see \help_update_10200()
+   * @see \help_post_update_help_topics_search()
+   * @see \help_post_update_help_topics_disable()
+   */
+  public function testHelpTopicsMerge(): void {
+    $moduleHandler = \Drupal::moduleHandler();
+    $this->assertTrue($moduleHandler->moduleExists('help'));
+    $this->assertFalse($moduleHandler->moduleExists('help_topics'));
+    $this->assertTrue($moduleHandler->moduleExists('search'));
+
+    $this->assertFalse(\Drupal::database()->schema()->tableExists('help_search_items'));
+
+    // No configuration present.
+    $this->assertNull(SearchPage::load('help_search'));
+    $this->assertNull(Block::load('claro_help_search'));
+
+    // Run updates.
+    $this->runUpdates();
+
+    $this->assertFalse(\Drupal::moduleHandler()->moduleExists('help_topics'));
+
+    $this->assertTrue(\Drupal::database()->schema()->tableExists('help_search_items'));
+
+    // Search module's configuration is installed.
+    $this->assertNotNull(Block::load('claro_help_search'));
+    $this->assertNotNull(SearchPage::load('help_search'));
+  }
+
+}

core/modules/help/tests/src/Functional/Update/HelpTopicsUninstall.php

@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Functional\Update;
+
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+
+/**
+ * Tests merging help topics module when the module is enabled.
+ *
+ * @group Update
+ * @group #slow
+ */
+class HelpTopicsUninstall extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setDatabaseDumpFiles() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../../system/tests/fixtures/update/drupal-9.4.0.bare.standard.php.gz',
+      __DIR__ . '/../../../../tests/fixtures/update/help-topics-3087499.php',
+    ];
+  }
+
+  /**
+   * Tests upgrading help module for help topics.
+   *
+   * @see \help_update_10200()
+   * @see \help_post_update_help_topics_search()
+   * @see \help_post_update_help_topics_uninstall()
+   */
+  public function testHelpTopicsMerge(): void {
+    $module_handler = \Drupal::moduleHandler();
+    $this->assertTrue($module_handler->moduleExists('help'));
+    $this->assertTrue($module_handler->moduleExists('help_topics'));
+    $this->assertTrue($module_handler->moduleExists('search'));
+
+    $this->assertFalse(\Drupal::database()->schema()->tableExists('help_search_items'));
+
+    $dependencies = $this
+      ->config('search.page.help_search')
+      ->get('dependencies.module');
+    $this->assertTrue(in_array('help_topics', $dependencies, TRUE));
+    $this->assertFalse(in_array('help', $dependencies, TRUE));
+
+    // Run updates.
+    $this->runUpdates();
+
+    $this->assertFalse(\Drupal::moduleHandler()->moduleExists('help_topics'));
+
+    $this->assertTrue(\Drupal::database()->schema()->tableExists('help_search_items'));
+
+    $dependencies = $this
+      ->config('search.page.help_search')
+      ->get('dependencies.module');
+    $this->assertFalse(in_array('help_topics', $dependencies, TRUE));
+    $this->assertTrue(in_array('help', $dependencies, TRUE));
+  }
+
+}

core/modules/help/tests/src/Kernel/HelpEmptyPageTest.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Kernel;
+
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\Routing\RouteMatch;
+use Drupal\help_test\SupernovaGenerator;
+use Drupal\KernelTests\KernelTestBase;
+
+/**
+ * Tests the empty HTML page.
+ *
+ * @group help
+ */
+class HelpEmptyPageTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['system', 'help_test', 'user', 'path_alias'];
+
+  /**
+   * {@inheritdoc}
+   */
+  public function register(ContainerBuilder $container) {
+    parent::register($container);
+
+    $container->set('url_generator', new SupernovaGenerator());
+  }
+
+  /**
+   * Ensures that no URL generator is called on a page without hook_help().
+   */
+  public function testEmptyHookHelp(): void {
+    $all_modules = \Drupal::service('extension.list.module')->getList();
+    $all_modules = array_filter($all_modules, function ($module) {
+      // Filter contrib, hidden, already enabled modules and modules in the
+      // Testing package.
+      if ($module->origin !== 'core' || !empty($module->info['hidden']) || $module->status == TRUE || $module->info['package'] == 'Testing') {
+        return FALSE;
+      }
+      return TRUE;
+    });
+
+    $this->enableModules(array_keys($all_modules));
+    $this->installEntitySchema('menu_link_content');
+
+    $route = \Drupal::service('router.route_provider')->getRouteByName('<front>');
+    \Drupal::service('module_handler')->invokeAll('help', ['<front>', new RouteMatch('<front>', $route)]);
+  }
+
+}

core/modules/help/tests/src/Kernel/HelpSearchPluginTest.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Kernel;
+
+use Drupal\Core\Access\AccessibleInterface;
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\search\Plugin\SearchIndexingInterface;
+
+/**
+ * Tests search plugin behaviors.
+ *
+ * @group help
+ *
+ * @see \Drupal\help\Plugin\Search\HelpSearch
+ */
+class HelpSearchPluginTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = ['help', 'search'];
+
+  /**
+   * Tests search plugin annotation and interfaces.
+   */
+  public function testAnnotation(): void {
+    /** @var \Drupal\search\SearchPluginManager $manager */
+    $manager = \Drupal::service('plugin.manager.search');
+    /** @var \Drupal\help\Plugin\Search\HelpSearch $plugin */
+    $plugin = $manager->createInstance('help_search');
+    $this->assertInstanceOf(AccessibleInterface::class, $plugin);
+    $this->assertInstanceOf(SearchIndexingInterface::class, $plugin);
+    $this->assertSame('Help', (string) $plugin->getPluginDefinition()['title']);
+    $this->assertTrue($plugin->usesAdminTheme());
+  }
+
+}

core/modules/help/tests/src/Unit/HelpTopicDiscoveryTest.php

@@ -0,0 +1,246 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Unit;
+
+use Drupal\Component\Discovery\DiscoveryException;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+use Drupal\Core\StringTranslation\TranslatableMarkup;
+use Drupal\help\HelpTopicDiscovery;
+use Drupal\help\HelpTopicTwig;
+use Drupal\Tests\UnitTestCase;
+use org\bovigo\vfs\vfsStream;
+
+/**
+ * @coversDefaultClass \Drupal\help\HelpTopicDiscovery
+ * @group help
+ */
+class HelpTopicDiscoveryTest extends UnitTestCase {
+
+  /**
+   * @covers ::findAll
+   */
+  public function testDiscoveryExceptionMissingLabel(): void {
+    vfsStream::setup('root');
+
+    vfsStream::create([
+      'modules' => [
+        'test' => [
+          'help_topics' => [
+            // The content of the help topic does not matter.
+            'test.topic.html.twig' => '',
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['test' => vfsStream::url('root/modules/test/help_topics')]);
+
+    $this->expectException(DiscoveryException::class);
+    $this->expectExceptionMessage("vfs://root/modules/test/help_topics/test.topic.html.twig does not contain the required key with name='label'");
+    $discovery->getDefinitions();
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testDiscoveryExceptionInvalidYamlKey(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: 'A label'
+foo: bar
+---
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'test' => [
+          'help_topics' => [
+            'test.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['test' => vfsStream::url('root/modules/test/help_topics')]);
+
+    $this->expectException(DiscoveryException::class);
+    $this->expectExceptionMessage("vfs://root/modules/test/help_topics/test.topic.html.twig contains invalid key='foo'");
+    $discovery->getDefinitions();
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testDiscoveryExceptionInvalidTopLevel(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: 'A label'
+top_level: bar
+---
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'test' => [
+          'help_topics' => [
+            'test.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['test' => vfsStream::url('root/modules/test/help_topics')]);
+
+    $this->expectException(DiscoveryException::class);
+    $this->expectExceptionMessage("vfs://root/modules/test/help_topics/test.topic.html.twig contains invalid value for 'top_level' key, the value must be a Boolean");
+    $discovery->getDefinitions();
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testDiscoveryExceptionInvalidRelated(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: 'A label'
+related: "one, two"
+---
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'test' => [
+          'help_topics' => [
+            'test.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['test' => vfsStream::url('root/modules/test/help_topics')]);
+
+    $this->expectException(DiscoveryException::class);
+    $this->expectExceptionMessage("vfs://root/modules/test/help_topics/test.topic.html.twig contains invalid value for 'related' key, the value must be an array of strings");
+    $discovery->getDefinitions();
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testHelpTopicsExtensionProviderSpecialCase(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: Test
+---
+<h2>Test</h2>
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'help' => [
+          'help_topics' => [
+            'core.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['help' => vfsStream::url('root/modules/help/help_topics')]);
+    $this->assertArrayHasKey('core.topic', $discovery->getDefinitions());
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testHelpTopicsInCore(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: Test
+---
+<h2>Test</h2>
+EOF;
+
+    vfsStream::create([
+      'core' => [
+        'help_topics' => [
+          'core.topic.html.twig' => $topic_content,
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['core' => vfsStream::url('root/core/help_topics')]);
+    $this->assertArrayHasKey('core.topic', $discovery->getDefinitions());
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testHelpTopicsBrokenYaml(): void {
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+foo : [bar}
+---
+<h2>Test</h2>
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'help' => [
+          'help_topics' => [
+            'core.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['help' => vfsStream::url('root/modules/help/help_topics')]);
+    $this->expectException(DiscoveryException::class);
+    $this->expectExceptionMessage("Malformed YAML in help topic \"vfs://root/modules/help/help_topics/core.topic.html.twig\":");
+    $discovery->getDefinitions();
+  }
+
+  /**
+   * @covers ::findAll
+   */
+  public function testHelpTopicsDefinition(): void {
+    $container = new ContainerBuilder();
+    $container->set('string_translation', $this->getStringTranslationStub());
+    \Drupal::setContainer($container);
+
+    vfsStream::setup('root');
+    $topic_content = <<<EOF
+---
+label: 'Test'
+top_level: true
+related:
+  - one
+  - two
+  - three
+---
+<h2>Test</h2>
+EOF;
+
+    vfsStream::create([
+      'modules' => [
+        'foo' => [
+          'help_topics' => [
+            'foo.topic.html.twig' => $topic_content,
+          ],
+        ],
+      ],
+    ]);
+    $discovery = new HelpTopicDiscovery(['foo' => vfsStream::url('root/modules/foo/help_topics')]);
+    $definition = $discovery->getDefinitions()['foo.topic'];
+    $this->assertEquals('Test', $definition['label']);
+    $this->assertInstanceOf(TranslatableMarkup::class, $definition['label']);
+    $this->assertTrue($definition['top_level']);
+    // Each related plugin ID should be trimmed.
+    $this->assertSame(['one', 'two', 'three'], $definition['related']);
+    $this->assertSame('foo', $definition['provider']);
+    $this->assertSame(HelpTopicTwig::class, $definition['class']);
+    $this->assertSame(vfsStream::url('root/modules/foo/help_topics/foo.topic.html.twig'), $definition['_discovered_file_path']);
+    $this->assertSame('foo.topic', $definition['id']);
+  }
+
+}

core/modules/help/tests/src/Unit/HelpTopicTwigLoaderTest.php

@@ -0,0 +1,134 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Unit;
+
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Extension\ThemeHandlerInterface;
+use Drupal\help\HelpTopicTwigLoader;
+use Drupal\Tests\UnitTestCase;
+use org\bovigo\vfs\vfsStream;
+use Twig\Error\LoaderError;
+
+/**
+ * Unit test for the HelpTopicTwigLoader class.
+ *
+ * @coversDefaultClass \Drupal\help\HelpTopicTwigLoader
+ * @group help
+ */
+class HelpTopicTwigLoaderTest extends UnitTestCase {
+
+  /**
+   * The help topic loader instance to test.
+   *
+   * @var \Drupal\help\HelpTopicTwigLoader
+   */
+  protected $helpLoader;
+
+  /**
+   * The virtual directories to use in testing.
+   *
+   * @var array
+   */
+  protected $directories;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->setUpVfs();
+
+    $module_handler = $this->createMock(ModuleHandlerInterface::class);
+    $module_handler
+      ->method('getModuleDirectories')
+      ->willReturn($this->directories['module']);
+
+    /** @var \Drupal\Core\Extension\ThemeHandlerInterface|\Prophecy\Prophecy\ObjectProphecy $module_handler */
+    $theme_handler = $this->createMock(ThemeHandlerInterface::class);
+    $theme_handler
+      ->method('getThemeDirectories')
+      ->willReturn($this->directories['theme']);
+
+    $this->helpLoader = new HelpTopicTwigLoader('\fake\root\path', $module_handler, $theme_handler);
+  }
+
+  /**
+   * @covers ::__construct
+   */
+  public function testConstructor(): void {
+    // Verify that the module/theme directories were added in the constructor,
+    // and non-existent directories were omitted.
+    $paths = $this->helpLoader->getPaths(HelpTopicTwigLoader::MAIN_NAMESPACE);
+    $this->assertCount(2, $paths);
+    $this->assertContains($this->directories['module']['test'] . '/help_topics', $paths);
+    $this->assertContains($this->directories['theme']['test'] . '/help_topics', $paths);
+  }
+
+  /**
+   * @covers ::getSourceContext
+   */
+  public function testGetSourceContext(): void {
+    $source = $this->helpLoader->getSourceContext('@' . HelpTopicTwigLoader::MAIN_NAMESPACE . '/test.topic.html.twig');
+    $this->assertEquals('{% line 4 %}<h2>Test</h2>', $source->getCode());
+  }
+
+  /**
+   * @covers ::getSourceContext
+   */
+  public function testGetSourceContextException(): void {
+    $this->expectException(LoaderError::class);
+    $this->expectExceptionMessage("Malformed YAML in help topic \"vfs://root/modules/test/help_topics/test.invalid_yaml.html.twig\":");
+
+    $this->helpLoader->getSourceContext('@' . HelpTopicTwigLoader::MAIN_NAMESPACE . '/test.invalid_yaml.html.twig');
+  }
+
+  /**
+   * Sets up the virtual file system.
+   */
+  protected function setUpVfs() {
+    $content = <<<EOF
+---
+label: Test
+---
+<h2>Test</h2>
+EOF;
+    $invalid_content = <<<EOF
+---
+foo : [bar}
+---
+<h2>Test</h2>
+EOF;
+    $help_topics_dir = [
+      'help_topics' => [
+        'test.topic.html.twig' => $content,
+        'test.invalid_yaml.html.twig' => $invalid_content,
+      ],
+    ];
+
+    vfsStream::setup('root');
+    vfsStream::create([
+      'modules' => [
+        'test' => $help_topics_dir,
+      ],
+      'themes' => [
+        'test' => $help_topics_dir,
+      ],
+    ]);
+
+    $this->directories = [
+      'root' => vfsStream::url('root'),
+      'module' => [
+        'test' => vfsStream::url('root/modules/test'),
+        'not_a_dir' => vfsStream::url('root/modules/not_a_dir'),
+      ],
+      'theme' => [
+        'test' => vfsStream::url('root/themes/test'),
+        'not_a_dir' => vfsStream::url('root/themes/not_a_dir'),
+      ],
+    ];
+  }
+
+}

core/modules/help/tests/src/Unit/HelpTopicTwigTest.php

@@ -0,0 +1,115 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\help\Unit;
+
+use Drupal\Core\Cache\Cache;
+use Drupal\help\HelpTopicTwig;
+use Drupal\Tests\UnitTestCase;
+use Twig\Template;
+use Twig\TemplateWrapper;
+
+/**
+ * Unit test for the HelpTopicTwig class.
+ *
+ * Note that the toUrl() and toLink() methods are not covered, because they
+ * have calls to new Url() and new Link() in them, so they cannot be unit
+ * tested.
+ *
+ * @coversDefaultClass \Drupal\help\HelpTopicTwig
+ * @group help
+ */
+class HelpTopicTwigTest extends UnitTestCase {
+
+  /**
+   * The help topic instance to test.
+   *
+   * @var \Drupal\help\HelpTopicTwig
+   */
+  protected $helpTopic;
+
+  /**
+   * The plugin information to use for setting up a test topic.
+   *
+   * @var array
+   */
+  const PLUGIN_INFORMATION = [
+    'id' => 'test.topic',
+    'provider' => 'test',
+    'label' => 'This is the topic label',
+    'top_level' => TRUE,
+    'related' => ['something'],
+    'body' => '<p>This is the topic body</p>',
+  ];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    $this->helpTopic = new HelpTopicTwig([],
+      self::PLUGIN_INFORMATION['id'],
+      self::PLUGIN_INFORMATION,
+      $this->getTwigMock());
+  }
+
+  /**
+   * @covers ::getBody
+   * @covers ::getLabel
+   */
+  public function testText(): void {
+    $this->assertEquals($this->helpTopic->getBody(),
+      ['#markup' => self::PLUGIN_INFORMATION['body']]);
+    $this->assertEquals($this->helpTopic->getLabel(),
+      self::PLUGIN_INFORMATION['label']);
+  }
+
+  /**
+   * @covers ::getProvider
+   * @covers ::isTopLevel
+   * @covers ::getRelated
+   */
+  public function testDefinition(): void {
+    $this->assertEquals($this->helpTopic->getProvider(),
+      self::PLUGIN_INFORMATION['provider']);
+    $this->assertEquals($this->helpTopic->isTopLevel(),
+      self::PLUGIN_INFORMATION['top_level']);
+    $this->assertEquals($this->helpTopic->getRelated(),
+      self::PLUGIN_INFORMATION['related']);
+  }
+
+  /**
+   * @covers ::getCacheContexts
+   * @covers ::getCacheTags
+   * @covers ::getCacheMaxAge
+   */
+  public function testCacheInfo(): void {
+    $this->assertEquals([], $this->helpTopic->getCacheContexts());
+    $this->assertEquals(['core.extension'], $this->helpTopic->getCacheTags());
+    $this->assertEquals(Cache::PERMANENT, $this->helpTopic->getCacheMaxAge());
+  }
+
+  /**
+   * Creates a mock Twig loader class for the test.
+   */
+  protected function getTwigMock() {
+    $twig = $this
+      ->getMockBuilder('Drupal\Core\Template\TwigEnvironment')
+      ->disableOriginalConstructor()
+      ->getMock();
+
+    $template = $this->getMockForAbstractClass(Template::class, [$twig], '', TRUE, TRUE, TRUE, ['render']);
+    $template
+      ->method('render')
+      ->willReturn(self::PLUGIN_INFORMATION['body']);
+
+    $twig
+      ->method('load')
+      ->willReturn(new TemplateWrapper($twig, $template));
+
+    return $twig;
+  }
+
+}

core/modules/help/tests/themes/help_topics_test_theme/help_topics/help_topics_test_theme.test.html.twig

@@ -0,0 +1,7 @@
+---
+label: 'XYZ Help Test theme'
+top_level: true
+related:
+  - help_topics_test.additional
+---
+<p>{% trans %}This is a theme provided topic.{% endtrans %}</p>

core/modules/help/tests/themes/help_topics_test_theme/help_topics_test_theme.info.yml

@@ -0,0 +1,10 @@
+name: Test Help Topics
+type: theme
+base theme: stable9
+description: A theme to test help topics.
+# version: VERSION
+
+# Information added by Drupal.org packaging script on 2024-07-04
+version: '10.3.1'
+project: 'drupal'
+datestamp: 1720094222