FileValidationTestSubscriber.php

<?php

declare (strict_types=1);
namespace Drupal\file_validator_test\EventSubscriber;

use Drupal\file\Validation\FileValidationEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Provides a validation listener for file validation tests.
 */
class FileValidationTestSubscriber implements EventSubscriberInterface {
  
  /**
   * Handles the file validation event.
   *
   * @param \Drupal\file\Validation\FileValidationEvent $event
   *   The event.
   */
  public function onFileValidation(FileValidationEvent $event) : void {
    _file_test_log_call('validate', [
      $event->file
        ->id(),
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() : array {
    return [
      FileValidationEvent::class => 'onFileValidation',
    ];
  }

}