'Construct a new blockdevice for testing purposes.'

def _get_free_blockdevice(self):

    volume = self.loopback_api.create_volume(dataset_id=uuid4(), size=LOOPBACK_MINIMUM_ALLOCATABLE_SIZE)
    self.loopback_api.attach_volume(volume.blockdevice_id, self.loopback_api.compute_instance_id())
    return self.loopback_api.get_device_path(volume.blockdevice_id)
