def METHOD_NAME(self):
    return_value = [{"name": "table", "columns": []}]
    with mock.patch("redash.query_runner.pg.PostgreSQL.get_schema") as patched_get_schema:
        patched_get_schema.return_value = return_value
        schema = self.factory.data_source.get_schema()
        self.assertEqual(return_value, schema)