'``create()`` returns a ``Deferred`` that fires with a ``Volume``.'

def test_create_result(self):

    pool = FilesystemStoragePool(FilePath(self.mktemp()))
    service = VolumeService(FilePath(self.mktemp()), pool, reactor=Clock())
    service.startService()
    d = service.create(service.get(MY_VOLUME))
    self.assertEqual(self.successResultOf(d), Volume(node_id=service.node_id, name=MY_VOLUME, service=service))
