class MediaTemplateSuggestionsTest

class MediaTemplateSuggestionsTest extends MediaFunctionalTestBase {
  
  /**
   * Modules to install.
   *
   * @var array
   */
  protected static $modules = [
    'media',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * Tests template suggestions from media_theme_suggestions_media().
   */
  public function testMediaThemeHookSuggestions() {
    $media_type = $this->createMediaType('test', [
      'queue_thumbnail_downloads' => FALSE,
    ]);
    // Create media item to be rendered.
    $media = Media::create([
      'bundle' => $media_type->id(),
      'name' => 'Unnamed',
    ]);
    $media->save();
    $view_mode = 'full';
    // Simulate theming of the media item.
    $build = \Drupal::entityTypeManager()->getViewBuilder('media')
      ->view($media, $view_mode);
    $variables['elements'] = $build;
    $suggestions = \Drupal::moduleHandler()->invokeAll('theme_suggestions_media', [
      $variables,
    ]);
    $this->assertSame($suggestions, [
      'media__full',
      'media__' . $media_type->id(),
      'media__' . $media_type->id() . '__full',
      'media__source_' . $media_type->getSource()
        ->getPluginId(),
    ], 'Found expected media suggestions.');
  }

}