def test_unique_instance_id_if_not_provided(self):
        a = LoopbackBlockDeviceAPI.from_path(root_path=b'')
        b = LoopbackBlockDeviceAPI.from_path(root_path=b'')
        self.assertNotEqual(
            a.compute_instance_id(),
            b.compute_instance_id(),
        )
Calling constructor with empty instance id creates a different
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/test/test_blockdevice.py/LoopbackBlockDeviceAPIConstructorTests.test_unique_instance_id_if_not_provided