AssetManager\Service\AssetManagerServiceFactory::createService PHP Method

    public function createService(ServiceLocatorInterface $serviceLocator)
    {
        return $this($serviceLocator, AssetManager::class);
    }

 public function testCreateService()
 {
     $assetFilterManager = new AssetFilterManager();
     $assetCacheManager = $this->getMockBuilder(AssetCacheManager::class)->disableOriginalConstructor()->getMock();
     $serviceManager = new ServiceManager();
     $serviceManager->setService(AggregateResolver::class, $this->getMock(ResolverInterface::class));
     $serviceManager->setService(AssetFilterManager::class, $assetFilterManager);
     $serviceManager->setService(AssetCacheManager::class, $assetCacheManager);
     $serviceManager->setService('config', array('asset_manager' => array('Dummy data', 'Bacon')));
     $factory = new AssetManagerServiceFactory();
     $this->assertInstanceOf(AssetManager::class, $factory->createService($serviceManager));
 }