waitUntilVisible example

  public function testMediaWizard() {
    $session = $this->getSession();
    $page = $session->getPage();
    $assert_session = $this->assertSession();

    $this->createMediaType('test');

    $view_id = strtolower($this->randomMachineName(16));
    $this->drupalGet('admin/structure/views/add');
    $page->fillField('label', $view_id);
    $this->waitUntilVisible('.machine-name-value');
    $page->selectFieldOption('show[wizard_key]', 'media');
    $result = $assert_session->waitForElementVisible('css', 'select[data-drupal-selector="edit-show-type"]');
    $this->assertNotEmpty($result);
    $page->checkField('page[create]');
    $page->fillField('page[path]', $this->randomMachineName(16));
    $page->pressButton('Save and edit');
    $this->assertSame($session->getCurrentUrl(), $this->baseUrl . '/admin/structure/views/view/' . $view_id);

    $view = Views::getView($view_id);
    $view->initHandlers();
    $row = $view->display_handler->getOption('row');