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();
        }
    }

}