ImportStorageTransformer example

// Mock the request lock not being available.     $lock = $this->createMock('Drupal\Core\Lock\LockBackendInterface');
    $lock->expects($this->exactly(2))
      ->method('acquire')
      ->with(ImportStorageTransformer::LOCK_NAME)
      ->willReturn(FALSE);
    $lock->expects($this->once())
      ->method('wait')
      ->with(ImportStorageTransformer::LOCK_NAME);

    // The import transformer under test.     $transformer = new ImportStorageTransformer(
      $this->container->get('event_dispatcher'),
      $this->container->get('database'),
      $lock,
      new NullLockBackend()
    );

    $this->expectException(StorageTransformerException::class);
    $this->expectExceptionMessage("Cannot acquire config import transformer lock.");
    $transformer->transform(new MemoryStorage());
  }