def test_returns_service(self):
        reactor = MemoryReactor()
        endpoint = TCP4ServerEndpoint(reactor, 6789)
        verifyObject(IService, create_api_service(
            ConfigurationPersistenceService(reactor, FilePath(self.mktemp())),
            ClusterStateService(reactor), endpoint, ClientContextFactory()))
``create_api_service`` returns an object providing ``IService``.
dataset/ETHPy150Open ClusterHQ/flocker/flocker/control/test/test_httpapi.py/CreateAPIServiceTests.test_returns_service