'```VolumeService.handoff()`` changes the owner node ID of the local
volume to the new owner\'s node ID.'

def test_handoff_changes_node_id(self):

    origin_service = create_volume_service(self)
    destination_service = create_volume_service(self)
    created = origin_service.create(origin_service.get(MY_VOLUME))
    def got_volume(volume):
        return origin_service.handoff(volume, LocalVolumeManager(destination_service))
    created.addCallback(got_volume)
    created.addCallback((lambda _: origin_service.enumerate()))
    def got_origin_volumes(volumes):
        expected_volume = Volume(node_id=destination_service.node_id, name=MY_VOLUME, service=origin_service)
        self.assertEqual(list(volumes), [expected_volume])
    created.addCallback(got_origin_volumes)
    return created
