clean install

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

@@ -0,0 +1,6 @@
+name: 'Help Page Test'
+type: module
+description: 'Module to test the help page.'
+package: Testing
+version: VERSION
+hidden: true

web/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 '';
+}

web/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'

web/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().'];
+  }
+
+}

web/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 [];
+  }
+
+}

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

@@ -0,0 +1,5 @@
+name: help_test
+type: module
+package: Testing
+dependencies:
+  - drupal:help

web/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
+}

web/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();
+  }
+
+}

web/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>

web/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>
+

web/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>

web/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
+---

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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>

web/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'

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

@@ -0,0 +1,8 @@
+# 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

web/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);
+}

web/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'

web/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

web/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;
+  }
+
+}

web/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;
+  }
+
+}

web/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');
+    }
+  }
+
+}

web/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;
+  }
+
+}

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

@@ -0,0 +1,6 @@
+name: 'Help Topics Twig Tester'
+type: module
+description: 'Support module for help testing.'
+package: Testing
+dependencies:
+  - drupal:help

web/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 }

web/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(),
+    ];
+  }
+
+}

web/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);
+  }
+
+}

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

@@ -0,0 +1,6 @@
+name: 'More Help Page Test'
+type: module
+description: 'Module to test the help page.'
+package: Testing
+version: VERSION
+hidden: true

web/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;
+}