class BlockTestBase

abstract class BlockTestBase extends BrowserTestBase {
  
  /**
   * Modules to install.
   *
   * @var array
   */
  protected static $modules = [
    'block',
    'filter',
    'test_page_test',
    'help',
    'block_test',
  ];
  
  /**
   * A list of theme regions to test.
   *
   * @var array
   */
  protected $regions;
  
  /**
   * A test user with administrative privileges.
   *
   * @var \Drupal\user\UserInterface
   */
  protected $adminUser;
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() {
    parent::setUp();
    // Use the test page as the front page.
    $this->config('system.site')
      ->set('page.front', '/test-page')
      ->save();
    // Create Full HTML text format.
    $full_html_format = FilterFormat::create([
      'format' => 'full_html',
      'name' => 'Full HTML',
    ]);
    $full_html_format->save();
    // Create and log in an administrative user having access to the Full HTML
    // text format.
    $this->adminUser = $this->drupalCreateUser([
      'administer blocks',
      $full_html_format->getPermissionName(),
      'access administration pages',
    ]);
    $this->drupalLogin($this->adminUser);
    // Define the existing regions.
    $this->regions = [
      'header',
      'sidebar_first',
      'content',
      'sidebar_second',
      'footer',
    ];
    $block_storage = $this->container
      ->get('entity_type.manager')
      ->getStorage('block');
    $blocks = $block_storage->loadByProperties([
      'theme' => $this->config('system.theme')
        ->get('default'),
    ]);
    foreach ($blocks as $block) {
      $block->delete();
    }
  }

}