DecoratedServiceTest.php

<?php

namespace Drupal\Tests\system\Kernel;

use Drupal\Component\DependencyInjection\ReverseContainer;
use Drupal\decorated_service_test\TestServiceDecorator;
use Drupal\KernelTests\KernelTestBase;

/**
 * Test handling of decorated services in DependencySerializationTraitPass.
 *
 * @group system
 */
class DecoratedServiceTest extends KernelTestBase {
    protected static $modules = [
        'decorated_service_test',
    ];
    
    /**
     * Check that decorated services keep their original service ID.
     */
    public function testDecoratedServiceId() {
        // Service decorated once.
        $test_service = $this->container
            ->get('test_service');
        $this->assertEquals('test_service', $this->container
            ->get(ReverseContainer::class)
            ->getId($test_service));
        $this->assertInstanceOf(TestServiceDecorator::class, $test_service);
        // Service decorated twice.
        $test_service2 = $this->container
            ->get('test_service2');
        $this->assertEquals('test_service2', $this->container
            ->get(ReverseContainer::class)
            ->getId($test_service2));
        $this->assertInstanceOf(TestServiceDecorator::class, $test_service2);
    }

}