DestructableServiceTest.php

<?php

declare (strict_types=1);
namespace Drupal\FunctionalTests\HttpKernel;

use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Url;
use Drupal\Tests\BrowserTestBase;

/**
 * Tests invocation of services performing deferred tasks after response flush.
 *
 * @see \Drupal\Core\DestructableInterface
 *
 * @group Http
 */
class DestructableServiceTest extends BrowserTestBase {
    
    /**
     * {@inheritdoc}
     */
    protected static $modules = [
        'system',
        'destructable_test',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    public function testDestructableServiceExecutionOrder() : void {
        $file_system = $this->container
            ->get('file_system');
        assert($file_system instanceof FileSystemInterface);
        $semaphore = $file_system->tempnam($file_system->getTempDirectory(), 'destructable_semaphore');
        $this->drupalGet(Url::fromRoute('destructable', [], [
            'query' => [
                'semaphore' => $semaphore,
            ],
        ]));
        // This should be false as the response should flush before running the
        // test service.
        $this->assertEmpty(file_get_contents($semaphore), 'Destructable service did not run when response flushed to client.');
        // The destructable service will sleep for 3 seconds, then run.
        // To ensure no race conditions on slow test runners, wait another 3s.
        sleep(6);
        $this->assertTrue(file_get_contents($semaphore) === 'ran', 'Destructable service did run.');
    }

}