@app.post("/third")
    def post_third(item1: Item):
        return item1  # pragma: nocover

    client = TestClient(app)
    with warnings.catch_warnings(record=True) as w:
        warnings.simplefilter("always")
        client.get("/openapi.json")
        assert len(w) >= 2
        duplicate_warnings = [
            warning for warning in w if issubclass(warning.category, UserWarning)
        ]