Issue #3276217 by lauriii, Wim Leers: [drupalMedia] add tests to confirm GHS...

    $this->assertNotEmpty($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://drupal.org" 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://drupal.org"]'));

    $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://drupal.org"] > 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.

   */