{"name": "baz", "price": "baz"},
    ]


client = TestClient(app)


def test_invalid():
    with pytest.raises(ResponseValidationError):
        client.get("/items/invalid")


def test_invalid_none():
    with pytest.raises(ResponseValidationError):
        client.get("/items/invalidnone")


def test_valid_none_data():
    response = client.get("/items/validnone")
    data = response.json()

class Item(BaseModel):
    name: str
    price: Optional[float] = None
    owner_ids: Optional[List[int]] = None

app = FastAPI()

@app.get("/items/invalidnone", response_model=Item)
def get_invalid_none():
    return None
```

...calling the path `/items/invalidnone` will raise an error, because `None` is not a valid type for the `response_model` declared with `Item`.