Issue #2910320 by murilohp, malik.kotob: Validating managed files should...

   * Render API callback: Validates the managed_file element.

   */

  public static function validateManagedFile(&$element, FormStateInterface $form_state, &$complete_form) {

    $clicked_button = end($form_state->getTriggeringElement()['#parents']);

    $triggering_element = $form_state->getTriggeringElement();

    $clicked_button = isset($triggering_element['#parents']) ? end($triggering_element['#parents']) : '';

    if ($clicked_button != 'remove_button' && !empty($element['fids']['#value'])) {

      $fids = $element['fids']['#value'];

      foreach ($fids as $fid) {

<?php

namespace Drupal\Tests\file\Kernel;

use Drupal\Core\Form\FormInterface;

use Drupal\Core\Form\FormState;

use Drupal\Core\Form\FormStateInterface;

/**

 * Managed file element test.

 *

 * @group file

 *

 * @see \Drupal\file\Element\ManagedFile

 */

class ManagedFileTest extends FileManagedUnitTestBase implements FormInterface {

  /**

   * {@inheritdoc}

   */

  public function getFormId() {

    return 'form_test_managed_file';

  }

  /**

   * {@inheritdoc}

   */

  public function buildForm(array $form, FormStateInterface $form_state) {

    $form['managed_file'] = [

      '#type' => 'managed_file',

    ];

    return $form;

  }

  /**

   * {@inheritdoc}

   */

  public function validateForm(array &$form, FormStateInterface $form_state) {}

  /**

   * {@inheritdoc}

   */

  public function submitForm(array &$form, FormStateInterface $form_state) {}

  /**

   * Tests that managed file elements can be programmatically submitted.

   */

  public function testManagedFileElement() {

    $form_state = new FormState();

    $values['managed_file'] = NULL;

    $form_state->setValues($values);

    $this->container->get('form_builder')->submitForm($this, $form_state);

    // Should submit without any errors.

    $this->assertEquals(0, count($form_state->getErrors()));

  }

}