'From the given list of volumes, find volumes created by tests which are
older than the maximum age.
:param timedelta maximum_age: The oldest a volume may be without being
considered old enough to include in the result.
:param list all_volumes: The libcloud volumes representing all the
volumes we can see on a particular cloud service.
:rtype: ``VolumeActions``'

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)
