def METHOD_NAME(self):
    app = client_feature_flags.ClientFeatureFlagsMiddleware(self._echo_app)
    server = werkzeug_test.Client(app, wrappers.Response)
    with self.assertRaisesRegex(
        errors.InvalidArgumentError, "cannot be JSON decoded."
    ):
        response = server.get(
            "",
            query_string={
                "tensorBoardFeatureFlags": "some_invalid_json {} {}",
            },
        )