'Instances of ``BlockDeviceVolume`` sort in the same order as a tuple
made up of the ``blockdevice_id``, ``dataset_id``, ``size``, and
``attached_to`` fields would sort.'

@given(blockdevice_volumes, blockdevice_volumes)
def test_stable_sort_order(self, one, another):

    self.assertThat(sorted([one, another]), Equals(sorted([one, another], key=(lambda volume: (volume.blockdevice_id, volume.dataset_id, volume.size, volume.attached_to)))))
