@callback_router.get(
    "{$callback_url}/callback/", responses={400: {"model": CustomModel}}
)
def callback_route():
    pass  # pragma: no cover


@app.post("/", callbacks=callback_router.routes)
def main_route(callback_url: HttpUrl):
    pass  # pragma: no cover


client = TestClient(app)


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text