responses={404: {"model": List[Message]}},
    )
    def post_subrouter(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    router.include_router(sub_router)
    app.include_router(router, generate_unique_id_function=custom_generate_unique_id3)
    client = TestClient(app)
    response = client.get("/openapi.json")
    data = response.json()
    assert data == {