response = client.get("/no_response_model-annotation_json_response_class")
    assert response.status_code == 200, response.text
    assert response.json() == {"foo": "bar"}


def test_invalid_response_model_field():
    app = FastAPI()
    with pytest.raises(FastAPIError) as e:

        @app.get("/")
        def read_root() -> Union[Response, None]:
            return Response(content="Foo")  # pragma: no cover