diff --git a/core/drupalci.yml b/core/drupalci.yml
index cd92d8102d..8878f959f6 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -3,49 +3,16 @@
 # https://www.drupal.org/drupalorg/docs/drupal-ci/customizing-drupalci-testing
 _phpunit_testgroups_to_execute: &testgroups
   # Default: all of Drupal core's test suite runs.
-  testgroups: '--all'
+  testgroups: '--class "\Drupal\Tests\ckeditor5\FunctionalJavascript\MediaTest"'
   # Alternative: run only the tests for one particular module.
   # testgroups: '--module ckeditor5'
 build:
   assessment:
     testing:
-      # Run code quality checks.
-      container_command.commit-checks:
-        commands:
-          - "core/scripts/dev/commit-code-check.sh --drupalci"
-        halt-on-fail: true
-      # run_tests task is executed several times in order of performance speeds.
-      # halt-on-fail can be set on the run_tests tasks in order to fail fast.
-      # suppress-deprecations is false in order to be alerted to usages of
-      # deprecated code.
-      run_tests.phpunit:
-        types: 'PHPUnit-Unit'
-        suppress-deprecations: false
-        halt-on-fail: false
-        <<: *testgroups
-      run_tests.kernel:
-        types: 'PHPUnit-Kernel'
-        suppress-deprecations: false
-        halt-on-fail: false
-        <<: *testgroups
-      run_tests.build:
-        # Limit concurrency due to disk space concerns.
-        concurrency: 15
-        types: 'PHPUnit-Build'
-        suppress-deprecations: false
-        halt-on-fail: false
-        <<: *testgroups
-      run_tests.functional:
-        types: 'PHPUnit-Functional'
-        suppress-deprecations: false
-        halt-on-fail: false
-        <<: *testgroups
       run_tests.javascript:
         concurrency: 15
         types: 'PHPUnit-FunctionalJavascript'
         suppress-deprecations: false
         halt-on-fail: false
         <<: *testgroups
-      # Run nightwatch testing.
-      # @see https://www.drupal.org/project/drupal/issues/2869825
-      nightwatchjs: {}
+        repeat: 500
diff --git a/core/modules/ckeditor5/tests/src/FunctionalJavascript/MediaTest.php b/core/modules/ckeditor5/tests/src/FunctionalJavascript/MediaTest.php
index ec69d7f39e..8f7239ba32 100644
--- a/core/modules/ckeditor5/tests/src/FunctionalJavascript/MediaTest.php
+++ b/core/modules/ckeditor5/tests/src/FunctionalJavascript/MediaTest.php
@@ -230,1124 +230,6 @@ function (ConstraintViolation $v) {
     $this->drupalLogin($this->adminUser);
   }
 
-  /**
-   * Tests that `<drupal-media>` is converted into a block element.
-   */
-  public function testConversion() {
-    // Wrap the `<drupal-media>` markup in a `<p>`.
-    $original_value = $this->host->body->value;
-    $this->host->body->value = '<p>foo' . $original_value . '</p>';
-    $this->host->save();
-
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-    $assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]', 1000);
-    $editor_html = $this->getEditorDataAsHtmlString();
-    // Observe that `<drupal-media>` was moved into its own block element.
-    $this->assertEquals('<p>foo</p>' . $original_value, str_replace('&nbsp;', '', $editor_html));
-  }
-
-  /**
-   * Tests that only <drupal-media> tags are processed.
-   *
-   * @see \Drupal\Tests\media\Kernel\MediaEmbedFilterTest::testOnlyDrupalMediaTagProcessed()
-   */
-  public function testOnlyDrupalMediaTagProcessed() {
-    $original_value = $this->host->body->value;
-    $this->host->body->value = str_replace('drupal-media', 'p', $original_value);
-    $this->host->save();
-
-    // Assert that `<p data-* …>` is not upcast into a CKEditor Widget.
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-    $this->assertEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]', 1000));
-    $assert_session->elementNotExists('css', '.ck-widget.drupal-media');
-
-    $this->host->body->value = $original_value;
-    $this->host->save();
-
-    // Assert that `<drupal-media data-* …>` is upcast into a CKEditor Widget.
-    $this->getSession()->reload();
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]'));
-    $assert_session->elementExists('css', '.ck-widget.drupal-media');
-  }
-
-  /**
-   * Tests that arbitrary attributes are allowed via GHS.
-   */
-  public function testMediaArbitraryHtml() {
-    $assert_session = $this->assertSession();
-
-    $editor = Editor::load('test_format');
-    $settings = $editor->getSettings();
-
-    // Allow the data-foo attribute in drupal-media via GHS. Also, add support
-    // for div's with data-foo attribute to ensure that drupal-media elements
-    // can be wrapped with other block elements.
-    $settings['plugins']['ckeditor5_sourceEditing']['allowed_tags'] = ['<drupal-media data-foo>', '<div data-bar>'];
-    $editor->setSettings($settings);
-    $editor->save();
-
-    $filter_format = $editor->getFilterFormat();
-    $filter_format->setFilterConfig('filter_html', [
-      'status' => TRUE,
-      'settings' => [
-        'allowed_html' => '<p> <br> <strong> <em> <a href> <drupal-media data-entity-type data-entity-uuid data-align data-caption alt data-foo data-view-mode> <div data-bar>',
-      ],
-    ]);
-    $filter_format->save();
-    $this->assertSame([], array_map(
-      function (ConstraintViolation $v) {
-        return (string) $v->getMessage();
-      },
-      iterator_to_array(CKEditor5::validatePair(
-        Editor::load('test_format'),
-        FilterFormat::load('test_format')
-      ))
-    ));
-
-    // Add data-foo use to an existing drupal-media tag.
-    $original_value = $this->host->body->value;
-    $this->host->body->value = '<div data-bar="baz">' . str_replace('drupal-media', 'drupal-media data-foo="bar" ', $original_value) . '</div>';
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-
-    // Confirm data-foo is present in the drupal-media preview.
-    $this->assertNotEmpty($upcasted_media = $assert_session->waitForElementVisible('css', '.ck-widget.drupal-media'));
-    $this->assertFalse($upcasted_media->hasAttribute('data-foo'));
-    $this->assertNotEmpty($preview = $assert_session->waitForElementVisible('css', '.ck-widget.drupal-media > [data-drupal-media-preview="ready"] > .media', 30000));
-    $this->assertEquals('bar', $preview->getAttribute('data-foo'));
-
-    // Confirm that the media is wrapped by the div on the editing view.
-    $assert_session->elementExists('css', 'div[data-bar="baz"] > .drupal-media');
-
-    // Confirm data-foo is not stripped from source.
-    $this->assertSourceAttributeSame('data-foo', 'bar');
-
-    // Confirm that drupal-media is wrapped by the div.
-    $editor_dom = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($editor_dom->query('//div[@data-bar="baz"]/drupal-media'));
-  }
-
-  /**
-   * Ensures arbitrary attributes can be added on links wrapping media via GHS.
-   *
-   * @dataProvider providerLinkability
-   */
-  public function testLinkedMediaArbitraryHtml(bool $unrestricted): void {
-    $assert_session = $this->assertSession();
-
-    $editor = Editor::load('test_format');
-    $settings = $editor->getSettings();
-    $filter_format = $editor->getFilterFormat();
-    if ($unrestricted) {
-      $filter_format
-        ->setFilterConfig('filter_html', ['status' => FALSE]);
-    }
-    else {
-      // Allow the data-foo attribute in <a> via GHS. Also, add support for div's
-      // with data-foo attribute to ensure that linked drupal-media elements can
-      // be wrapped with <div>.
-      $settings['plugins']['ckeditor5_sourceEditing']['allowed_tags'] = ['<a data-foo>', '<div data-bar>'];
-      $editor->setSettings($settings);
-      $filter_format->setFilterConfig('filter_html', [
-        'status' => TRUE,
-        'settings' => [
-          'allowed_html' => '<p> <br> <strong> <em> <a href data-foo> <drupal-media data-entity-type data-entity-uuid data-align data-caption alt data-view-mode> <div data-bar>',
-        ],
-      ]);
-    }
-    $editor->save();
-    $filter_format->save();
-    $this->assertSame([], array_map(
-      function (ConstraintViolation $v) {
-        return (string) $v->getMessage();
-      },
-      iterator_to_array(CKEditor5::validatePair(
-        Editor::load('test_format'),
-        FilterFormat::load('test_format')
-      ))
-    ));
-
-    // Wrap the existing drupal-media tag with a div and an a that include
-    // attributes allowed via GHS.
-    $original_value = $this->host->body->value;
-    $this->host->body->value = '<div data-bar="baz"><a href="https://example.com" data-foo="bar">' . $original_value . '</a></div>';
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-
-    // Confirm data-foo is present in the editing view.
-    $this->assertNotEmpty($link = $assert_session->waitForElementVisible('css', 'a[href="https://example.com"]'));
-    $this->assertEquals('bar', $link->getAttribute('data-foo'));
-
-    // Confirm that the media is wrapped by the div on the editing view.
-    $assert_session->elementExists('css', 'div[data-bar="baz"] > .drupal-media > a[href="https://example.com"] > div[data-drupal-media-preview]');
-
-    // Confirm that drupal-media is wrapped by the div and a, and that GHS has
-    // retained arbitrary HTML allowed by source editing.
-    $editor_dom = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($editor_dom->query('//div[@data-bar="baz"]/a[@data-foo="bar"]/drupal-media'));
-  }
-
-  /**
-   * Tests that failed media embed preview requests inform the end user.
-   */
-  public function testErrorMessages() {
-    // This test currently frequently causes the SQLite database to lock, so
-    // skip the test on SQLite until the issue can be resolved.
-    // @todo https://www.drupal.org/project/drupal/issues/3273626
-    if (Database::getConnection()->driver() === 'sqlite') {
-      $this->markTestSkipped('Test frequently causes a locked database on SQLite');
-    }
-
-    // Assert that a request to the `media.filter.preview` route that does not
-    // result in a 200 response (due to server error or network error) is
-    // handled in the JavaScript by displaying the expected error message.
-    // @see core/modules/media/js/media_embed_ckeditor.theme.js
-    // @see js/ckeditor5_plugins/drupalMedia/src/drupalmediaediting.js
-    $this->container->get('state')->set('test_media_filter_controller_throw_error', TRUE);
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-    $assert_session->waitForElementVisible('css', '.ck-widget.drupal-media');
-    $this->assertEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]', 1000));
-    $assert_session->elementNotExists('css', '.ck-widget.drupal-media .media');
-    $this->assertNotEmpty($assert_session->waitForText('An error occurred while trying to preview the media. Please save your work and reload this page.'));
-    // Now assert that the error doesn't appear when the override to force an
-    // error is removed.
-    $this->container->get('state')->set('test_media_filter_controller_throw_error', FALSE);
-    $this->getSession()->reload();
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]'));
-
-    // There's a second kind of error message that comes from the back end
-    // that happens when the media uuid can't be converted to a media preview.
-    // In this case, the error will appear in a the themeable
-    // media-embed-error.html template.  We have a hook altering the css
-    // classes to test the twig template is working properly and picking up our
-    // extra class.
-    // @see \Drupal\media\Plugin\Filter\MediaEmbed::renderMissingMediaIndicator()
-    // @see core/modules/media/templates/media-embed-error.html.twig
-    // @see media_test_embed_preprocess_media_embed_error()
-    $original_value = $this->host->body->value;
-    $this->host->body->value = str_replace($this->media->uuid(), 'invalid_uuid', $original_value);
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-widget.drupal-media .this-error-message-is-themeable'));
-
-    // Test when using the starterkit_theme theme, an additional class is added
-    // to the error, which is supported by
-    // stable9/templates/content/media-embed-error.html.twig.
-    $this->assertTrue($this->container->get('theme_installer')->install(['starterkit_theme']));
-    $this->config('system.theme')
-      ->set('default', 'starterkit_theme')
-      ->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-widget.drupal-media .this-error-message-is-themeable'));
-
-    // Test that restoring a valid UUID results in the media embed preview
-    // displaying.
-    $this->host->body->value = $original_value;
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]'));
-    $assert_session->elementNotExists('css', '.ck-widget.drupal-media .this-error-message-is-themeable');
-  }
-
-  /**
-   * The CKEditor Widget must load a preview generated using the default theme.
-   */
-  public function testPreviewUsesDefaultThemeAndIsClientCacheable() {
-    // Make the node edit form use the admin theme, like on most Drupal sites.
-    $this->config('node.settings')
-      ->set('use_admin_theme', TRUE)
-      ->save();
-
-    // Allow the test user to view the admin theme.
-    $this->adminUser->addRole($this->drupalCreateRole(['view the administration theme']));
-    $this->adminUser->save();
-
-    // Configure a different default and admin theme, like on most Drupal sites.
-    $this->config('system.theme')
-      ->set('default', 'stable9')
-      ->set('admin', 'starterkit_theme')
-      ->save();
-
-    // Assert that when looking at an embedded entity in the CKEditor Widget,
-    // the preview is generated using the default theme, not the admin theme.
-    // @see media_test_embed_entity_view_alter()
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]'));
-    $element = $assert_session->elementExists('css', '[data-media-embed-test-active-theme]');
-    $this->assertSame('stable9', $element->getAttribute('data-media-embed-test-active-theme'));
-    // Assert that the first preview request transferred >500 B over the wire.
-    // Then toggle source mode on and off. This causes the CKEditor widget to be
-    // destroyed and then reconstructed. Assert that during this reconstruction,
-    // a second request is sent. This second request should have transferred 0
-    // bytes: the browser should have cached the response, thus resulting in a
-    // much better user experience.
-    $this->assertGreaterThan(500, $this->getLastPreviewRequestTransferSize());
-    $this->pressEditorButton('Source');
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-source-editing-area'));
-    // CKEditor 5 is very smart: if no changes were made in the Source Editing
-    // Area, it will not rerender the contents. In this test, we
-    // want to verify that Media preview responses are cached on the client side
-    // so it is essential that rerendering occurs. To achieve this, we append a
-    // single space.
-    $source_text_area = $this->getSession()->getPage()->find('css', '[name="body[0][value]"] + .ck-editor textarea');
-    $source_text_area->setValue($source_text_area->getValue() . ' ');
-    $this->pressEditorButton('Source');
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'img[src*="image-test.png"]'));
-    $this->assertSame(0, $this->getLastPreviewRequestTransferSize());
-  }
-
-  /**
-   * Tests caption editing in the CKEditor widget.
-   */
-  public function testEditableCaption() {
-    $page = $this->getSession()->getPage();
-    $assert_session = $this->assertSession();
-    // Test that setting caption to blank string doesn't break 'Edit media'
-    // button.
-    $original_value = $this->host->body->value;
-    $this->host->body->value = str_replace('data-caption="baz"', 'data-caption=""', $original_value);
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    // Wait for the media preview to load.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-    $assert_session->elementExists('css', '[data-drupal-media-preview][aria-label="Screaming hairy armadillo"]');
-    $assert_session->elementContains('css', 'figcaption', '');
-    $assert_session->elementAttributeContains('css', 'figcaption', 'data-placeholder', 'Enter media caption');
-
-    // Test if you leave the caption blank, but change another attribute,
-    // such as the alt text, the editable caption is still there and the edit
-    // button still exists.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    // Click the "Override media image alternative text" button.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-
-    // Fill in the alt field and submit.
-    $alt_override_input->setValue('Gold star for robot boy.');
-    $this->getBalloonButton('Save')->click();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.drupal-media img[alt*="Gold star for robot boy."]'));
-    $this->assertEquals('', $assert_session->waitForElement('css', '.drupal-media figcaption')->getText());
-    $assert_session->elementAttributeContains('css', '.drupal-media figcaption', 'data-placeholder', 'Enter media caption');
-
-    // Restore caption in saved body value.
-    $original_value = $this->host->body->value;
-    $this->host->body->value = str_replace('data-caption=""', 'data-caption="baz"', $original_value);
-    $this->host->save();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-    $this->assertNotEmpty($figcaption = $assert_session->waitForElement('css', '.drupal-media figcaption'));
-    $this->assertSame('baz', $figcaption->getHtml());
-
-    // Ensure that the media contextual toolbar is visible when figcaption is
-    // selected.
-    $this->selectTextInsideElement('.drupal-media figcaption');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    $expected_buttons = [
-      'Toggle caption off',
-      'Link media',
-      'Override media image alternative text',
-      // Check only one of the element style buttons since that is sufficient
-      // for confirming that element style buttons are visible in the toolbar.
-      'Break text',
-    ];
-    foreach ($expected_buttons as $expected_button) {
-      $this->assertNotEmpty($this->getBalloonButton($expected_button));
-    }
-
-    // Ensure that caption can be toggled off from the toolbar.
-    $this->getBalloonButton('Toggle caption off')->click();
-    $assert_session->assertNoElementAfterWait('css', 'figcaption');
-
-    // Ensure that caption can be toggled on from the toolbar.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    $this->getBalloonButton('Toggle caption on')->click();
-    $this->assertNotEmpty($figcaption = $assert_session->waitForElementVisible('css', '.drupal-media figcaption'));
-
-    // Ensure that the media contextual toolbar is visible after toggling
-    // caption on.
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-
-    // Type into the widget's caption element.
-    $this->selectTextInsideElement('.drupal-media figcaption');
-    $figcaption->setValue('Llamas are the most awesome ever');
-    $editor_dom = $this->getEditorDataAsDom();
-    $this->assertEquals('Llamas are the most awesome ever', $editor_dom->getElementsByTagName('drupal-media')->item(0)->getAttribute('data-caption'));
-
-    // Ensure that the caption can be changed to bold.
-    $this->assertNotEmpty($figcaption = $assert_session->waitForElement('css', '.drupal-media figcaption'));
-    $this->selectTextInsideElement('.drupal-media figcaption');
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption.ck-editor__nested-editable'));
-    $this->pressEditorButton('Bold');
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption > strong'));
-    $this->assertEquals('<strong>Llamas are the most awesome ever</strong>', $figcaption->getHtml());
-    $editor_dom = $this->getEditorDataAsDom();
-    $this->assertEquals('<strong>Llamas are the most awesome ever</strong>', $editor_dom->getElementsByTagName('drupal-media')->item(0)->getAttribute('data-caption'));
-
-    // Ensure that bold can be removed from the caption.
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption > strong'));
-    $this->selectTextInsideElement('.drupal-media figcaption > strong');
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption.ck-editor__nested-editable'));
-    $this->pressEditorButton('Bold');
-    $this->assertTrue($assert_session->waitForElementRemoved('css', '.drupal-media figcaption > strong'));
-    $this->assertNotEmpty($figcaption = $assert_session->waitForElement('css', '.drupal-media figcaption'));
-    $this->assertEquals('Llamas are the most awesome ever', $figcaption->getHtml());
-    $editor_dom = $this->getEditorDataAsDom();
-    $this->assertEquals('Llamas are the most awesome ever', $editor_dom->getElementsByTagName('drupal-media')->item(0)->getAttribute('data-caption'));
-
-    // Ensure that caption can contain elements such as <br>.
-    $this->pressEditorButton('Source');
-    $source_text_area = $assert_session->waitForElement('css', '.ck-source-editing-area textarea');
-    $source_text = $source_text_area->getValue();
-    $source_text_area->setValue(str_replace('data-caption="Llamas are the most awesome ever"', 'data-caption="Llamas are the most<br>awesome ever"', $source_text));
-    // Click source again to make source inactive.
-    $this->pressEditorButton('Source');
-    // Check that the source mode is toggled off.
-    $assert_session->elementNotExists('css', '.ck-source-editing-area textarea');
-    // Put back the caption as it was before.
-    $this->pressEditorButton('Source');
-    $source_text_area = $assert_session->waitForElement('css', '.ck-source-editing-area textarea');
-    $source_text = $source_text_area->getValue();
-    $source_text_area->setValue(str_replace('data-caption="Llamas are the most&lt;br&gt;awesome ever"', 'data-caption="Llamas are the most awesome ever"', $source_text));
-    // Click source again to make source inactive.
-    $this->pressEditorButton('Source');
-    // Check that the source mode is toggled off.
-    $assert_session->elementNotExists('css', '.ck-source-editing-area textarea');
-
-    // Ensure that caption can be linked.
-    $this->assertNotEmpty($figcaption = $assert_session->waitForElement('css', '.drupal-media figcaption'));
-    $figcaption->click();
-    $this->selectTextInsideElement('.drupal-media figcaption');
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption.ck-editor__nested-editable'));
-    $this->pressEditorButton('Link');
-    $this->assertVisibleBalloon('.ck-link-form');
-    $link_input = $page->find('css', '.ck-balloon-panel .ck-link-form input[type=text]');
-    $link_input->setValue('https://example.com');
-    $page->find('css', '.ck-balloon-panel .ck-link-form button[type=submit]')->click();
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.drupal-media figcaption > a'));
-    $this->assertEquals('<a class="ck-link_selected" href="https://example.com">Llamas are the most awesome ever</a>', $figcaption->getHtml());
-    $editor_dom = $this->getEditorDataAsDom();
-    $this->assertEquals('<a href="https://example.com">Llamas are the most awesome ever</a>', $editor_dom->getElementsByTagName('drupal-media')->item(0)->getAttribute('data-caption'));
-  }
-
-  /**
-   * Tests that the image media source's alt_field being disabled is respected.
-   *
-   * @see \Drupal\Tests\ckeditor5\Functional\MediaEntityMetadataApiTest::testApi()
-   */
-  public function testAltDisabled(): void {
-    // Disable the alt field for image media.
-    FieldConfig::loadByName('media', 'image', 'field_media_image')
-      ->setSetting('alt_field', FALSE)
-      ->save();
-
-    $assert_session = $this->assertSession();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    // Wait for the media preview to load.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-    // Test that by default no alt attribute is present on the drupal-media
-    // element.
-    $this->assertSourceAttributeSame('alt', NULL);
-    // Test that the preview shows the alt value from the media field's
-    // alt text.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img[alt*="default alt"]'));
-    // Test that clicking the media widget triggers a CKEditor balloon panel
-    // with a single button to override the alt text.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    // Assert that no "Override media image alternative text" button is visible.
-    $override_alt_button = $this->getBalloonButton('Override media image alternative text');
-    $this->assertFalse($override_alt_button->isVisible());
-  }
-
-  /**
-   * Tests the CKEditor 5 media plugin can override image media's alt attribute.
-   */
-  public function testAlt() {
-    $page = $this->getSession()->getPage();
-    $assert_session = $this->assertSession();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    // Wait for the media preview to load.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-    // Test that by default no alt attribute is present on the drupal-media
-    // element.
-    $this->assertSourceAttributeSame('alt', NULL);
-    // Test that the preview shows the alt value from the media field's
-    // alt text.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img[alt*="default alt"]'));
-    // Test that clicking the media widget triggers a CKEditor balloon panel
-    // with a single button to override the alt text.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    // Click the "Override media image alternative text" button.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    // Assert that the default alt text is visible in the UI.
-    $assert_session->elementTextEquals('css', '.ck-media-alternative-text-form__default-alt-text-value', 'default alt');
-    // Assert that the value is currently empty.
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-    $this->assertSame('', $alt_override_input->getValue());
-
-    // Fill in the alt field and submit.
-    // cSpell:disable-next-line
-    $who_is_zartan = 'Zartan is the leader of the Dreadnoks.';
-    $alt_override_input->setValue($who_is_zartan);
-    $this->getBalloonButton('Save')->click();
-
-    // Assert that the img within the media embed within the CKEditor contains
-    // the overridden alt text set in the dialog.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img[alt*="' . $who_is_zartan . '"]'));
-    // Ensure that the Drupal Media widget doesn't have alt attribute.
-    // @see https://www.drupal.org/project/drupal/issues/3248440
-    $assert_session->elementNotExists('css', '.ck-widget.drupal-media[alt]');
-    // Test `aria-label` attribute appears on the widget wrapper.
-    $assert_session->elementExists('css', '.ck-widget.drupal-media [aria-label="Screaming hairy armadillo"]');
-
-    // Test that the downcast drupal-media element now has the alt attribute
-    // entered in the balloon.
-    $this->assertSourceAttributeSame('alt', $who_is_zartan);
-
-    // The alt field should now display the override instead of the default.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-    $this->assertSame($who_is_zartan, $alt_override_input->getValue());
-    // Assert that the default alt text is still visible in the UI.
-    $assert_session->elementTextEquals('css', '.ck-media-alternative-text-form__default-alt-text-value', 'default alt');
-
-    // Test the process again with a different alt text to make sure it works
-    // the second time around.
-    $cobra_commander_bio = 'The supreme leader of the terrorist organization Cobra';
-    // Set the alt field to the new alt text.
-    $alt_override_input->setValue($cobra_commander_bio);
-    $this->getBalloonButton('Save')->click();
-    // Assert that the img within the media embed preview inside CKEditor 5
-    // contains the overridden alt text set in the balloon.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img[alt*="' . $cobra_commander_bio . '"]'));
-
-    // Test that the downcast drupal-media element now has the alt attribute
-    // entered in the dialog.
-    $this->assertSourceAttributeSame('alt', $cobra_commander_bio);
-
-    // The default value of the alt field should now display the override
-    // instead of the value on the media image field.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-    $this->assertSame($cobra_commander_bio, $alt_override_input->getValue());
-
-    // Test that setting alt value to two double quotes will signal to the
-    // MediaEmbed filter to unset the attribute on the media image field.
-    // We intentionally add a space after the two double quotes to test that the
-    // string is trimmed to two quotes.
-    $alt_override_input->setValue('"" ');
-    $this->getBalloonButton('Save')->click();
-    // Verify that the two double quote empty alt indicator ('""') set in
-    // the alt text form balloon has successfully resulted in a media image
-    // field with the alt attribute present but without a value.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '[data-media-embed-test-view-mode] img[alt=""]'));
-
-    // Test that the downcast drupal-media element's alt attribute now has the
-    // empty string indicator.
-    $this->assertSourceAttributeSame('alt', '""');
-
-    // Test that setting alt to back to an empty string within the balloon will
-    // restore the default alt value saved in to the media image field of the
-    // media item.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-    $alt_override_input->setValue('');
-    $this->getBalloonButton('Save')->click();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img[alt*="default alt"]'));
-
-    // Test that the downcast drupal-media element no longer has an alt
-    // attribute.
-    $this->assertSourceAttributeSame('alt', NULL);
-  }
-
-  /**
-   * Tests the CKEditor 5 media plugin loads the translated alt attribute.
-   */
-  public function testTranslationAlt() {
-    \Drupal::service('module_installer')->install(['language', 'content_translation']);
-    $this->resetAll();
-    ConfigurableLanguage::create(['id' => 'fr'])->save();
-    ContentLanguageSettings::loadByEntityTypeBundle('media', 'image')
-      ->setDefaultLangcode('en')
-      ->setLanguageAlterable(TRUE)
-      ->save();
-    $media = Media::create([
-      'bundle' => 'image',
-      'name' => 'Screaming hairy armadillo',
-      'field_media_image' => [
-        [
-          'target_id' => 1,
-          'alt' => 'default alt',
-          'title' => 'default title',
-        ],
-      ],
-    ]);
-    $media->save();
-    $media_fr = $media->addTranslation('fr');
-    $media_fr->name = "Tatou poilu hurlant";
-    $media_fr->field_media_image->setValue([
-      [
-        'target_id' => '1',
-        'alt' => "texte alternatif par défaut",
-        'title' => "titre alternatif par défaut",
-      ],
-    ]);
-    $media_fr->save();
-
-    ContentLanguageSettings::loadByEntityTypeBundle('node', 'blog')
-      ->setDefaultLangcode('en')
-      ->setLanguageAlterable(TRUE)
-      ->save();
-
-    $host = $this->createNode([
-      'type' => 'blog',
-      'title' => 'Animals with strange names',
-      'body' => [
-        'value' => '<drupal-media data-caption="baz" data-entity-type="media" data-entity-uuid="' . $media->uuid() . '"></drupal-media>',
-        'format' => 'test_format',
-      ],
-    ]);
-    $host->save();
-
-    $translation = $host->addTranslation('fr');
-    // cSpell:disable-next-line
-    $translation->title = 'Animaux avec des noms étranges';
-    $translation->body->value = $host->body->value;
-    $translation->body->format = $host->body->format;
-    $translation->save();
-
-    Role::load(RoleInterface::AUTHENTICATED_ID)
-      ->grantPermission('translate any entity')
-      ->save();
-
-    $page = $this->getSession()->getPage();
-    $assert_session = $this->assertSession();
-    $this->drupalGet('/fr/node/' . $host->id() . '/edit');
-    $this->waitForEditor();
-
-    // Test that the default alt attribute displays without an override.
-    // cSpell:disable-next-line
-    $this->assertNotEmpty($assert_session->waitForElementVisible('xpath', '//img[contains(@alt, "texte alternatif par défaut")]'));
-    // Test `aria-label` attribute appears on the preview wrapper.
-    // cSpell:disable-next-line
-    $assert_session->elementExists('css', '[data-drupal-media-preview][aria-label="Tatou poilu hurlant"]');
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    // Click the "Override media image alternative text" button.
-    $this->getBalloonButton('Override media image alternative text')->click();
-    $this->assertVisibleBalloon('.ck-media-alternative-text-form');
-    // Assert that the default alt on the UI is the default alt text from the
-    // media entity.
-    // cSpell:disable-next-line
-    $assert_session->elementTextEquals('css', '.ck-media-alternative-text-form__default-alt-text-value', 'texte alternatif par défaut');
-
-    // Fill in the alt field in the balloon form.
-    // cSpell:disable-next-line
-    $qui_est_zartan = 'Zartan est le chef des Dreadnoks.';
-    $alt_override_input = $page->find('css', '.ck-balloon-panel .ck-media-alternative-text-form input[type=text]');
-    $alt_override_input->setValue($qui_est_zartan);
-    $this->getBalloonButton('Save')->click();
-
-    // Assert that the img within the media embed within CKEditor 5 contains
-    // the overridden alt text set in CKEditor 5.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('xpath', '//img[contains(@alt, "' . $qui_est_zartan . '")]'));
-    $this->getSession()->switchToIFrame();
-    $page->pressButton('Save');
-    $assert_session->elementExists('xpath', '//img[contains(@alt, "' . $qui_est_zartan . '")]');
-  }
-
-  /**
-   * Tests linkability of the media CKEditor widget.
-   *
-   * Due to the very different HTML markup generated for the editing view and
-   * the data view, this is explicitly testing the "editingDowncast" and
-   * "dataDowncast" results. These are CKEditor 5 concepts.
-   *
-   * @see https://ckeditor.com/docs/ckeditor5/latest/framework/guides/architecture/editing-engine.html#conversion
-   *
-   * @dataProvider providerLinkability
-   */
-  public function testLinkability(bool $unrestricted) {
-    // Disable filter_html.
-    if ($unrestricted) {
-      FilterFormat::load('test_format')
-        ->setFilterConfig('filter_html', ['status' => FALSE])
-        ->save();
-    }
-
-    $page = $this->getSession()->getPage();
-
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-
-    // Initial state: the Drupal Media CKEditor Widget is not selected.
-    $drupalmedia = $assert_session->waitForElementVisible('css', '.ck-content .ck-widget.drupal-media');
-    $this->assertNotEmpty($drupalmedia);
-    $this->assertFalse($drupalmedia->hasClass('.ck-widget_selected'));
-
-    // Assert the "editingDowncast" HTML before making changes.
-    $assert_session->elementExists('css', '.ck-content .ck-widget.drupal-media > [data-drupal-media-preview]');
-
-    // Assert the "dataDowncast" HTML before making changes.
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query('//drupal-media'));
-    $this->assertEmpty($xpath->query('//a'));
-
-    // Assert the link button is present and not pressed.
-    $link_button = $this->getEditorButton('Link');
-    $this->assertSame('false', $link_button->getAttribute('aria-pressed'));
-
-    // Wait for the preview to load.
-    $preview = $assert_session->waitForElement('css', '.ck-content .ck-widget.drupal-media [data-drupal-media-preview="ready"]');
-    $this->assertNotEmpty($preview);
-
-    // Tests linking Drupal media.
-    $drupalmedia->click();
-    $this->assertTrue($drupalmedia->hasClass('ck-widget_selected'));
-    $this->assertEditorButtonEnabled('Link');
-    // Assert structure of image toolbar balloon.
-    $this->assertVisibleBalloon('.ck-toolbar[aria-label="Drupal Media toolbar"]');
-    $link_media_button = $this->getBalloonButton('Link media');
-    // Click the "Link media" button.
-    $this->assertSame('false', $link_media_button->getAttribute('aria-pressed'));
-    $link_media_button->press();
-    // Assert structure of link form balloon.
-    $balloon = $this->assertVisibleBalloon('.ck-link-form');
-    $url_input = $balloon->find('css', '.ck-labeled-field-view__input-wrapper .ck-input-text');
-    // Fill in link form balloon's <input> and hit "Save".
-    $url_input->setValue('http://linking-embedded-media.com');
-    $balloon->pressButton('Save');
-
-    // Assert the "editingDowncast" HTML after making changes. Assert the link
-    // exists, then assert the link exists. Then assert the expected DOM
-    // structure in detail.
-    $assert_session->elementExists('css', '.ck-content a[href="http://linking-embedded-media.com"]');
-    $assert_session->elementExists('css', '.ck-content .drupal-media.ck-widget > a[href="http://linking-embedded-media.com"] > div[aria-label] > article > div > img[src*="image-test.png"]');
-
-    // Assert the "dataDowncast" HTML after making changes.
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query('//drupal-media'));
-    $this->assertNotEmpty($xpath->query('//a[@href="http://linking-embedded-media.com"]'));
-    $this->assertNotEmpty($xpath->query('//a[@href="http://linking-embedded-media.com"]/drupal-media'));
-    // Ensure that the media caption is retained and not linked as a result of
-    // linking media.
-    $this->assertNotEmpty($xpath->query('//a[@href="http://linking-embedded-media.com"]/drupal-media[@data-caption="baz"]'));
-
-    // Add `class="trusted"` to the link.
-    $this->assertEmpty($xpath->query('//a[@href="http://linking-embedded-media.com" and @class="trusted"]'));
-    $this->pressEditorButton('Source');
-    $source_text_area = $assert_session->waitForElement('css', '.ck-source-editing-area textarea');
-    $this->assertNotEmpty($source_text_area);
-    $new_value = str_replace('<a ', '<a class="trusted" ', $source_text_area->getValue());
-    $source_text_area->setValue('<p>temp</p>');
-    $source_text_area->setValue($new_value);
-    $this->pressEditorButton('Source');
-
-    // When unrestricted, additional attributes on links should be retained.
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertCount($unrestricted ? 1 : 0, $xpath->query('//a[@href="http://linking-embedded-media.com" and @class="trusted"]'));
-
-    // Save the entity whose text field is being edited.
-    $page->pressButton('Save');
-
-    // Assert the HTML the end user sees.
-    $assert_session->elementExists('css', $unrestricted
-      ? 'a[href="http://linking-embedded-media.com"].trusted img[src*="image-test.png"]'
-      : 'a[href="http://linking-embedded-media.com"] img[src*="image-test.png"]');
-
-    // Go back to edit the now *linked* <drupal-media>. Everything from this
-    // point onwards is effectively testing "upcasting" and proving there is no
-    // data loss.
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-
-    // Assert the "dataDowncast" HTML before making changes.
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query('//drupal-media'));
-    $this->assertNotEmpty($xpath->query('//a[@href="http://linking-embedded-media.com"]'));
-    $this->assertNotEmpty($xpath->query('//a[@href="http://linking-embedded-media.com"]/drupal-media'));
-
-    // Tests unlinking media.
-    $drupalmedia->click();
-    $this->assertEditorButtonEnabled('Link');
-    $this->assertSame('true', $this->getEditorButton('Link')->getAttribute('aria-pressed'));
-    // Assert structure of Drupal media toolbar balloon.
-    $this->assertVisibleBalloon('.ck-toolbar[aria-label="Drupal Media toolbar"]');
-    $link_media_button = $this->getBalloonButton('Link media');
-    $this->assertSame('true', $link_media_button->getAttribute('aria-pressed'));
-    $link_media_button->click();
-    // Assert structure of link actions balloon.
-    $this->getBalloonButton('Edit link');
-    $unlink_image_button = $this->getBalloonButton('Unlink');
-    // Click the "Unlink" button.
-    $unlink_image_button->click();
-    $this->assertSame('false', $this->getEditorButton('Link')->getAttribute('aria-pressed'));
-
-    // Assert the "editingDowncast" HTML after making changes. Assert the link
-    // exists, then assert no link exists. Then assert the expected DOM
-    // structure in detail.
-    $assert_session->elementNotExists('css', '.ck-content a');
-    $assert_session->elementExists('css', '.ck-content .drupal-media.ck-widget > div[aria-label] > article > div > img[src*="image-test.png"]');
-
-    // Ensure that figcaption exists.
-    // @see https://www.drupal.org/project/drupal/issues/3268318
-    $assert_session->elementExists('css', '.ck-content .drupal-media.ck-widget > figcaption');
-
-    // Assert the "dataDowncast" HTML after making changes.
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query('//drupal-media'));
-    $this->assertEmpty($xpath->query('//a'));
-  }
-
-  public function providerLinkability(): array {
-    return [
-      'restricted' => [FALSE],
-      'unrestricted' => [TRUE],
-    ];
-  }
-
-  /**
-   * Ensure that manual link decorators work with linkable media.
-   *
-   * @dataProvider providerLinkability
-   */
-  public function testLinkManualDecorator(bool $unrestricted) {
-    \Drupal::service('module_installer')->install(['ckeditor5_manual_decorator_test']);
-    $this->resetAll();
-
-    $decorator = 'Open in a new tab';
-    $decorator_attributes = '[@target="_blank"][@rel="noopener noreferrer"][@class="link-new-tab"]';
-
-    // Disable filter_html.
-    if ($unrestricted) {
-      FilterFormat::load('test_format')
-        ->setFilterConfig('filter_html', ['status' => FALSE])
-        ->save();
-      $decorator = 'Pink color';
-      $decorator_attributes = '[@style="color:pink;"]';
-    }
-
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    $assert_session = $this->assertSession();
-    $page = $this->getSession()->getPage();
-
-    $this->assertNotEmpty($drupalmedia = $assert_session->waitForElementVisible('css', '.ck-content .ck-widget.drupal-media'));
-    $drupalmedia->click();
-    $this->assertVisibleBalloon('.ck-toolbar[aria-label="Drupal Media toolbar"]');
-
-    // Turn off caption, so we don't accidentally put our link in that text
-    // field instead of on the actual media.
-    $this->getBalloonButton('Toggle caption off')->click();
-    $assert_session->assertNoElementAfterWait('css', 'figure.drupal-media > figcaption');
-
-    $this->assertVisibleBalloon('.ck-toolbar[aria-label="Drupal Media toolbar"]');
-    $this->getBalloonButton('Link media')->click();
-
-    $balloon = $this->assertVisibleBalloon('.ck-link-form');
-    $url_input = $balloon->find('css', '.ck-labeled-field-view__input-wrapper .ck-input-text');
-    $url_input->setValue('http://linking-embedded-media.com');
-    $this->getBalloonButton($decorator)->click();
-    $balloon->pressButton('Save');
-
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.drupal-media a'));
-    $this->assertVisibleBalloon('.ck-link-actions');
-
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query("//a[@href='http://linking-embedded-media.com']$decorator_attributes"));
-    $this->assertNotEmpty($xpath->query("//a[@href='http://linking-embedded-media.com']$decorator_attributes/drupal-media"));
-
-    // Ensure that manual decorators upcast correctly.
-    $page->pressButton('Save');
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->assertNotEmpty($drupalmedia = $assert_session->waitForElementVisible('css', '.ck-content .ck-widget.drupal-media'));
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertNotEmpty($xpath->query("//a[@href='http://linking-embedded-media.com']$decorator_attributes"));
-    $this->assertNotEmpty($xpath->query("//a[@href='http://linking-embedded-media.com']$decorator_attributes/drupal-media"));
-
-    // Finally, ensure that media can be unlinked.
-    $drupalmedia->click();
-    $this->assertVisibleBalloon('.ck-toolbar[aria-label="Drupal Media toolbar"]');
-    $this->getBalloonButton('Link media')->click();
-    $this->assertVisibleBalloon('.ck-link-actions');
-    $this->getBalloonButton('Unlink')->click();
-
-    $this->assertTrue($assert_session->waitForElementRemoved('css', '.drupal-media a'));
-    $xpath = new \DOMXPath($this->getEditorDataAsDom());
-    $this->assertEmpty($xpath->query('//a'));
-    $this->assertNotEmpty($xpath->query('//drupal-media'));
-  }
-
-  /**
-   * Tests preview route access.
-   *
-   * @param bool $media_embed_enabled
-   *   Whether to test with media_embed filter enabled on the text format.
-   * @param bool $can_use_format
-   *   Whether the logged in user is allowed to use the text format.
-   *
-   * @dataProvider previewAccessProvider
-   */
-  public function testEmbedPreviewAccess($media_embed_enabled, $can_use_format) {
-    // Reconfigure the host entity's text format to suit our needs.
-    /** @var \Drupal\filter\FilterFormatInterface $format */
-    $format = FilterFormat::load($this->host->body->format);
-    $format->set('filters', [
-      'filter_align' => ['status' => TRUE],
-      'filter_caption' => ['status' => TRUE],
-      'media_embed' => ['status' => $media_embed_enabled],
-    ]);
-    $format->save();
-
-    $permissions = [
-      'bypass node access',
-    ];
-    if ($can_use_format) {
-      $permissions[] = $format->getPermissionName();
-    }
-    $this->drupalLogin($this->drupalCreateUser($permissions));
-    $this->drupalGet($this->host->toUrl('edit-form'));
-
-    $assert_session = $this->assertSession();
-    if ($can_use_format) {
-      $this->waitForEditor();
-      if ($media_embed_enabled) {
-        // The preview rendering, which in this test will use Starterkit theme's
-        // media.html.twig template, will fail without the CSRF token/header.
-        // @see ::testEmbeddedMediaPreviewWithCsrfToken()
-        $this->assertNotEmpty($assert_session->waitForElementVisible('css', 'article.media'));
-      }
-      else {
-        // If the filter isn't enabled, there won't be an error, but the
-        // preview shouldn't be rendered.
-        $assert_session->assertWaitOnAjaxRequest();
-        $assert_session->elementNotExists('css', 'article.media');
-      }
-    }
-    else {
-      $assert_session->pageTextContains('This field has been disabled because you do not have sufficient permissions to edit it.');
-    }
-  }
-
-  /**
-   * Data provider for ::testEmbedPreviewAccess.
-   */
-  public function previewAccessProvider() {
-    return [
-      'media_embed filter enabled' => [
-        TRUE,
-        TRUE,
-      ],
-      'media_embed filter disabled' => [
-        FALSE,
-        TRUE,
-      ],
-      'media_embed filter enabled, user not allowed to use text format' => [
-        TRUE,
-        FALSE,
-      ],
-    ];
-  }
-
-  /**
-   * Tests alignment integration.
-   *
-   * Tests that alignment is reflected onto the CKEditor Widget wrapper, that
-   * the media style toolbar allows altering the alignment and that the changes
-   * are reflected on the widget and downcast drupal-media tag.
-   */
-  public function testAlignment() {
-    $assert_session = $this->assertSession();
-    $page = $this->getSession()->getPage();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    // Wait for the media preview to load.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-
-    // Ensure that by default the "Break text" alignment option is selected.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    $this->assertTrue(($align_button = $this->getBalloonButton('Break text'))->hasClass('ck-on'));
-    $editor_dom = $this->getEditorDataAsDom();
-    $drupal_media_element = $editor_dom->getElementsByTagName('drupal-media')
-      ->item(0);
-    $this->assertFalse($drupal_media_element->hasAttribute('data-align'));
-    $this->getBalloonButton('Align center and break text')->click();
-
-    // Assert the alignment class exists after editing downcast.
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-widget.drupal-media.drupal-media-style-align-center'));
-    $editor_dom = $this->getEditorDataAsDom();
-    $drupal_media_element = $editor_dom->getElementsByTagName('drupal-media')
-      ->item(0);
-    $this->assertEquals('center', $drupal_media_element->getAttribute('data-align'));
-
-    $page->pressButton('Save');
-    // Check that the 'content has been updated' message status appears to confirm we left the editor.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.messages.messages--status'));
-    // Check that the class is correct in the front end.
-    $assert_session->elementExists('css', 'figure.align-center');
-    // Go back to the editor to check that the alignment class still exists.
-    $edit_url = $this->getSession()->getCurrentURL() . '/edit';
-    $this->drupalGet($edit_url);
-    $this->waitForEditor();
-    $assert_session->elementExists('css', '.ck-widget.drupal-media.drupal-media-style-align-center');
-
-    // Ensure that "Centered media" alignment option is selected.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    $this->assertTrue($this->getBalloonButton('Align center and break text')->hasClass('ck-on'));
-    $this->getBalloonButton('Break text')->click();
-    $this->assertTrue($assert_session->waitForElementRemoved('css', '.ck-widget.drupal-media.drupal-media-style-align-center'));
-    $editor_dom = $this->getEditorDataAsDom();
-    $drupal_media_element = $editor_dom->getElementsByTagName('drupal-media')
-      ->item(0);
-    $this->assertFalse($drupal_media_element->hasAttribute('data-align'));
-  }
-
-  /**
-   * Ensures that Drupal Media Styles can be displayed in a dropdown.
-   */
-  public function testDrupalMediaStyleInDropdown() {
-    \Drupal::service('module_installer')->install(['ckeditor5_drupalelementstyle_test']);
-    $this->resetAll();
-
-    $assert_session = $this->assertSession();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-    // Wait for the media preview to load.
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-widget.drupal-media img'));
-
-    // Ensure that by default the "Break text" alignment option is selected and
-    // that the split button title is displayed.
-    $this->click('.ck-widget.drupal-media');
-    $this->assertVisibleBalloon('[aria-label="Drupal Media toolbar"]');
-    $this->assertNotEmpty(($split_button = $this->getBalloonButton('Test title: Break text'))->hasClass('ck-on'));
-
-    // Ensure that the split button can be opened.
-    $split_button->click();
-    $this->assertNotEmpty($assert_session->waitForElementVisible('css', '.ck-dropdown__panel-visible'));
-
-    // Ensure that a button inside the split button can be clicked.
-    $this->assertNotEmpty($align_button = $this->getBalloonButton('Align center and break text'));
-    $align_button->click();
-
-    // Ensure that the "Align center and break text" option is selected and the
-    // split button title is displayed.
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-widget.drupal-media.drupal-media-style-align-center'));
-    $editor_dom = $this->getEditorDataAsDom();
-    $drupal_media_element = $editor_dom->getElementsByTagName('drupal-media')
-      ->item(0);
-    $this->assertEquals('center', $drupal_media_element->getAttribute('data-align'));
-    $this->assertNotEmpty(($this->getBalloonButton('Test title: Align center and break text'))->hasClass('ck-on'));
-  }
-
-  /**
-   * Tests Drupal Media Style with a CSS class.
-   */
-  public function testDrupalMediaStyleWithClass() {
-    $editor = Editor::load('test_format');
-    $editor->setSettings([
-      'toolbar' => [
-        'items' => [
-          'heading',
-          'sourceEditing',
-          'simpleBox',
-        ],
-      ],
-      'plugins' => [
-        'ckeditor5_heading' => [
-          'enabled_headings' => [
-            'heading1',
-          ],
-        ],
-        'ckeditor5_sourceEditing' => [
-          'allowed_tags' => [
-            '<div>',
-            '<section>',
-          ],
-        ],
-        'media_media' => [
-          'allow_view_mode_override' => TRUE,
-        ],
-      ],
-    ]);
-    $filter_format = $editor->getFilterFormat();
-    $filter_format->setFilterConfig('filter_html', [
-      'status' => TRUE,
-      'settings' => [
-        'allowed_html' => '<p> <br> <h1 class> <div class> <section class> <drupal-media data-entity-type data-entity-uuid data-align data-caption data-view-mode alt class="layercake-side">',
-      ],
-    ]);
-    $filter_format->save();
-    $editor->save();
-
-    $this->assertSame([], array_map(
-      function (ConstraintViolation $v) {
-        return (string) $v->getMessage();
-      },
-      iterator_to_array(CKEditor5::validatePair(
-        Editor::load('test_format'),
-        FilterFormat::load('test_format')
-      ))
-    ));
-
-    $assert_session = $this->assertSession();
-    $page = $this->getSession()->getPage();
-    $this->drupalGet($this->host->toUrl('edit-form'));
-    $this->waitForEditor();
-
-    $page->pressButton('Source');
-    $editor_dom = $this->getEditorDataAsDom();
-    $drupal_media_element = $editor_dom->getElementsByTagName('drupal-media')->item(0);
-
-    // Add `layercake-side` class which is used in `ckeditor5_test_layercake`,
-    // as well as an arbitrary class to compare behavior between these.
-    $drupal_media_element->setAttribute('class', 'layercake-side arbitrary-class');
-    $textarea = $page->find('css', '.ck-source-editing-area > textarea');
-    $textarea->setValue($editor_dom->C14N());
-    $page->pressButton('Source');
-
-    // Ensure that the `layercake-side` class is retained.
-    $this->assertNotEmpty($assert_session->waitForElement('css', '.ck-widget.drupal-media.layercake-side'));
-
-    // Ensure that the `arbitrary-class` class is removed.
-    $assert_session->elementNotExists('css', '.ck-widget.drupal-media.arbitrary-class');
-    $page->pressButton('Save');
-
-    // Check that the 'content has been updated' message status appears to confirm we left the editor.
-    $assert_session->waitForElementVisible('css', 'messages messages--status');
-
-    // Ensure that the class is correct in the front end.
-    $assert_session->elementExists('css', 'figure.layercake-side');
-    $assert_session->elementNotExists('css', 'figure.arbitrary-class');
-  }
-
   /**
    * Tests view mode integration.
    *
@@ -1627,50 +509,4 @@ public function providerTestViewMode(): array {
     ];
   }
 
-  /**
-   * Verifies value of an attribute on the downcast <drupal-media> element.
-   *
-   * Assumes CKEditor is in source mode.
-   *
-   * @param string $attribute
-   *   The attribute to check.
-   * @param string|null $value
-   *   Either a string value or if NULL, asserts that <drupal-media> element
-   *   doesn't have the attribute.
-   *
-   * @internal
-   */
-  protected function assertSourceAttributeSame(string $attribute, ?string $value): void {
-    $dom = $this->getEditorDataAsDom();
-    $drupal_media = (new \DOMXPath($dom))->query('//drupal-media');
-    $this->assertNotEmpty($drupal_media);
-    if ($value === NULL) {
-      $this->assertFalse($drupal_media[0]->hasAttribute($attribute));
-    }
-    else {
-      $this->assertSame($value, $drupal_media[0]->getAttribute($attribute));
-    }
-  }
-
-  /**
-   * Gets the transfer size of the last preview request.
-   *
-   * @return int
-   *   The size of the bytes transferred.
-   */
-  protected function getLastPreviewRequestTransferSize() {
-    $javascript = <<<JS
-(function(){
-  return window.performance
-    .getEntries()
-    .filter(function (entry) {
-      return entry.initiatorType == 'fetch' && entry.name.indexOf('/media/test_format/preview') !== -1;
-    })
-    .pop()
-    .transferSize;
-})()
-JS;
-    return $this->getSession()->evaluateScript($javascript);
-  }
-
 }