def METHOD_NAME(self):
    app = client_feature_flags.ClientFeatureFlagsMiddleware(self._echo_app)
    server = werkzeug_test.Client(app, wrappers.Response)
    response = server.get(
        "",
        headers=[
            (
                "X-TensorBoard-Feature-Flags",
                '{"a": "1", "b": "2"}',
            )
        ],
        query_string={"tensorBoardFeatureFlags": '{"a": "2", "c": "3"}'},
    )
    self._assert_ok(
        response,
        {
            "a": "1",
            "b": "2",
            "c": "3",
        },
    )