def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def test_volume_bootable(self):
        """Test setting and retrieving bootable flag of a volume"""
        for bool_bootable in [True, False]:
            self.volumes_client.set_bootable_volume(self.volume['id'],
                                                    bootable=bool_bootable)
            fetched_volume = self.volumes_client.show_volume(
                self.volume['id'])['volume']
            # Get Volume information
            # NOTE(masayukig): 'bootable' is "true" or "false" in the current
            # cinder implementation. So we need to cast boolean values to str
            # and make it lower to compare here.
            self.assertEqual(str(bool_bootable).lower(),
                             fetched_volume['bootable'])