def METHOD_NAME(self):
    with get_child_case() as case:
        index_map = case.get_index_map()
        case_copier = CaseCopier(DOMAIN, to_owner='new_owner_id')
        case_copier.copy_cases([case.case_id])
        # `CaseCopier.original_cases` does not include parent case
        index_attrs = case_copier._get_new_index_attrs(index_map['mother'])
        self.assertIsNone(index_attrs)