[Test] pytest에서 mocking 사용하기

import uvicorn
import aiohttp
from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI(docs_url="/swagger")


@app.get("/health_check")
async def health_check():
    return JSONResponse(content=dict(msg="ok"))


async def local_health_check():
    async with aiohttp.ClientSession() as session:
        async with session.get("http://10.0.0.1:8000/health_check") as response:
            result = await response.json()
    return result["msg"]


@app.get("/health_proxy")
async def health_proxy():
    msg = await local_health_check()
    return JSONResponse(content=dict(msg=msg))


if __name__ == "__main__":
    uvicorn.run("server:app", host="0.0.0.0")

from fastapi.testclient import TestClient

from server import app


client = TestClient(app)


# every test method must starts with test

def test_health_check():
    response = client.get("/health_check")
    assert response.status_code == 200
    assert response.json() == {"msg": "ok"}


def test_health_proxy():
    # fail (impossible to call health_check)
    response = client.get("/health_proxy")
    assert response.status_code == 200
    assert response.json() == {"msg": "ok"}


def test_health_proxy_with_mocking(mocker):
    mocker.patch("server.local_health_check", return_value="ok with mocking")

    response = client.get("/health_proxy")
    assert response.status_code == 200
    assert response.json() == {"msg": "ok with mocking"}

# 기본 실행
pytest mocking_test.py

# coverage 확인. --cov에 coverage를 확인하려는 src의 폴더를 지정
pytest --cov=. mocking_test.py