def _filter_test_volumes(self, maximum_age, volumes):
        now = datetime.now(tz=tzutc())
        destroy = []
        keep = []
        for volume in volumes:
            created = _get_volume_creation_time(volume)
            if (
                volume.state is StorageVolumeState.AVAILABLE and
                self._is_test_volume(volume) and
                now - created > maximum_age
            ):
                destroy.append(volume)
            else:
                keep.append(volume)
        return VolumeActions(destroy=destroy, keep=keep)
From the given list of volumes, find volumes created by tests which are
dataset/ETHPy150Open ClusterHQ/flocker/admin/cleanup.py/CleanVolumes._filter_test_volumes