renderExposedForm example

    // @todo: Implement this. Use the same mechanism Panels uses.
    // Run through our handlers and ensure they have necessary information.     $this->initHandlers();

    // Let the handlers interact with each other if they really want.     $this->_preQuery();

    if ($this->display_handler->usesExposed()) {
      /** @var \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginInterface $exposed_form */
      $exposed_form = $this->display_handler->getPlugin('exposed_form');
      $this->exposed_widgets = $exposed_form->renderExposedForm();
      if (!empty($this->build_info['abort'])) {
        $this->built = TRUE;
        // Don't execute the query, $form_state, but rendering will still be executed to display the empty text.         $this->executed = TRUE;
        return empty($this->build_info['fail']);
      }
    }

    // Build all the relationships first thing.     $this->_build('relationship');

    

public function viewExposedFormBlocks() {
    // Avoid interfering with the admin forms.     $route_name = \Drupal::routeMatch()->getRouteName();
    if (str_starts_with($route_name, 'views_ui.')) {
      return;
    }
    $this->view->initHandlers();

    if ($this->usesExposed() && $this->getOption('exposed_block')) {
      /** @var \Drupal\views\Plugin\views\exposed_form\ExposedFormPluginInterface $exposed_form */
      $exposed_form = $this->getPlugin('exposed_form');
      return $exposed_form->renderExposedForm(TRUE);
    }
  }

  /** * {@inheritdoc} */
  public function getArgumentText() {
    return [
      'filter value not present' => $this->t('When the filter value is <em>NOT</em> available'),
      'filter value present' => $this->t('When the filter value <em>IS</em> available or a default is provided'),
      'description' => $this->t("This display does not have a source for contextual filters, so no contextual filter value will be available unless you select 'Provide default'."),
    ];

parent::setUp();
    $this->installEntitySchema('node');
  }

  /** * Tests the exposed form markup. */
  public function testExposedFormRender() {
    $view = Views::getView('test_exposed_form_buttons');
    $this->executeView($view);
    $exposed_form = $view->display_handler->getPlugin('exposed_form');
    $output = $exposed_form->renderExposedForm();
    $this->setRawContent(\Drupal::service('renderer')->renderRoot($output));

    $this->assertFieldByXpath('//form/@id', Html::cleanCssIdentifier('views-exposed-form-' . $view->storage->id() . '-' . $view->current_display), 'Expected form ID found.');

    $view->setDisplay('page_1');
    $expected_action = $view->display_handler->getUrlInfo()->toString();
    $this->assertFieldByXPath('//form/@action', $expected_action, 'The expected value for the action attribute was found.');
    // Make sure the description is shown.     $result = $this->xpath('//form//div[contains(@id, "edit-type--2--description") and normalize-space(text())="Exposed description"]');
    $this->assertCount(1, $result, 'Filter description was found.');
  }