def METHOD_NAME(self):
    group_doc = {
        'name': 'g1',
        '_id': 'group1',
        'users': [self.user_id],
        'removed_users': set([]),
    }
    # re-process group with no change
    update_es_user_with_groups(group_doc)
    self._check_es_user(['group1'], ['g1'])
    group_doc['removed_users'].add(self.user_id)
    group_doc['users'] = []
    update_es_user_with_groups(group_doc)
    self._check_es_user(None, None)