def test_docker_override(self):
        dummy_docker_client = object()
        self.assertIs(
            dummy_docker_client,
            ApplicationNodeDeployer(
                u'example.com',
                docker_client=dummy_docker_client).docker_client
        )
``ApplicationNodeDeployer.docker_client`` can be overridden in the
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/test/test_container.py/ApplicationNodeDeployerAttributesTests.test_docker_override