UserLoginDecoratedTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\user\Functional;

use Drupal\user_auth_decorator_test\UserAuthDecorator;

/**
 * Ensure that login works as expected with a decorator.
 *
 * The decorator does not implement UserAuthenticationInterface.
 *
 * @group user
 */
class UserLoginDecoratedTest extends UserLoginTest {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'user_auth_decorator_test',
  ];
  
  /**
   * Test that the UserAuthDecorator is providing user.auth.
   */
  public function testServiceDecorated() : void {
    $service = \Drupal::service('user.auth');
    $this->assertInstanceOf(UserAuthDecorator::class, $service);
  }

}