assertHelpLink example

// The entire section for creating new media should only be displayed if     // the user can create at least one media of the type.     if ($create_media_types) {
      if (count($create_media_types) === 1) {
        $url = Url::fromRoute('entity.media.add_form')->setRouteParameter('media_type', $create_media_types[0]);
      }
      else {
        $url = Url::fromRoute('entity.media.add_page');
      }
      $this->assertHelpTexts([$create_header, $create_help], $fieldset_selector);
      $this->assertHelpLink(
        $fieldset,
        'media add page',
        [
          'target' => '_blank',
          'href' => $url->toString(),
        ]
      );
    }
    else {
      $this->assertNoHelpTexts([$create_header, $create_help]);
      $this->assertNoHelpLink($fieldset, 'media add page');
    }