},
)
async def c():
    return "c"


@router.get(
    "/d",
    responses={
        "400": {"description": "Error with str"},
        "5XX": {"model": ResponseModel},
        "default": {"model": ResponseModel},
    },
)
async def d():
    return "d"


app.include_router(router)


client = TestClient(app)


def test_a():
    response = client.get("/a")

from fastapi.testclient import TestClient
from pydantic import BaseModel, Field

app = FastAPI()


class ResponseModel(BaseModel):
    code: int = 200
    message: str = Field(default_factory=lambda: "Successful operation.")


@app.get(
    "/response_model_has_default_factory_return_dict",
    response_model=ResponseModel,
)
async def response_model_has_default_factory_return_dict():
    return {"code": 200}


@app.get(