Files
fastapi/tests/test_dump_json_fast_path.py

52 lines
1.4 KiB
Python

from unittest.mock import patch
from fastapi import FastAPI
from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient
from pydantic import BaseModel
class Item(BaseModel):
name: str
price: float
app = FastAPI()
@app.get("/default")
def get_default() -> Item:
return Item(name="widget", price=9.99)
@app.get("/explicit", response_class=JSONResponse)
def get_explicit() -> Item:
return Item(name="widget", price=9.99)
client = TestClient(app)
def test_default_response_class_skips_json_dumps():
"""When no response_class is set, the fast path serializes directly to
JSON bytes via Pydantic's dump_json and never calls json.dumps."""
with patch(
"starlette.responses.json.dumps", wraps=__import__("json").dumps
) as mock_dumps:
response = client.get("/default")
assert response.status_code == 200
assert response.json() == {"name": "widget", "price": 9.99}
mock_dumps.assert_not_called()
def test_explicit_response_class_uses_json_dumps():
"""When response_class is explicitly set to JSONResponse, the normal path
is used and json.dumps is called via JSONResponse.render()."""
with patch(
"starlette.responses.json.dumps", wraps=__import__("json").dumps
) as mock_dumps:
response = client.get("/explicit")
assert response.status_code == 200
assert response.json() == {"name": "widget", "price": 9.99}
mock_dumps.assert_called_once()