pytest 在单独的进程中请求 fastapi

Question

我正在尝试对使用 FastAPI 编写的 API 进行工作测试。

我在一个单独的进程中启动该服务，使用对服务的请求运行测试，并检查结果是否符合预期。

我已将关键部分提取到 PD 中的最小工作示例中。

使用主文件运行 MWE 工作正常。 但是，测试失败了。

• 为什么测试会失败？
• 我们应该如何测试 API？

PD：代码在 GIST中，但现在也在这里：

自述文件

# Minimal example to ask in StackOverflow

Pytest does not allow to start a process with a service and tests requests to it,
  at least not in the most straightforward way IMHO.

I may be missing something, or I may be doing something wrong.
Hence, I share this short code in a gist, to ask.

## How to run it

The dependencies are: `fastapi pytest requests uvicorn`.
You may install them with your package / environment manager of choice,
  or use `pipenv install` with the provided `Pipfile`.

To run the code in the environment (e.g. `pipenv shell`), run: `python3 mwe.py`.
You should see everything is `OK`.

To run the test, run in the environment: `pytest`.
This does not work for me, the request times out.

mwe.py

import fastapi, multiprocessing, requests, time, uvicorn

app = fastapi.FastAPI()


@app.get('/ok')
def ok():
    return 'OK'


class service:
    def __enter__(self):
        def run_service():
            uvicorn.run('mwe:app', host='0.0.0.0', port=8000, reload=True)
        self.service = multiprocessing.Process(target=run_service)
        self.service.start()
        time.sleep(10)

    def __exit__(self, *args):
        self.service.terminate()


def main():
    with service():
        return requests.get('http://127.0.0.1:8000/ok').ok


if __name__ == '__main__':
    print('🆖🆗'[main()])

文件

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
pytest = "*"
fastapi = "*"
requests = "*"
uvicorn = "*"

[requires]
python_version = "3.10"
python_full_version = "3.10.6"

test_mwe.py

from mwe import main

def test_main():
    assert main()

Answer 1

来自官方文档的测试示例

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/")
async def read_main():
    return {"msg": "Hello World"}


client = TestClient(app)


def test_read_main():
    response = client.get("/")
    assert response.status_code == 200
    assert response.json() == {"msg": "Hello World"}

因此，对于您所附的 git 中的示例，它可以重写为如下所示：

def test_get_ok():
    response = client.get("/ok")
    assert response.status_code == 200
    assert response.text() == 'OK'

简而言之，很难描述如何正确测试 API，但您可以举个例子，在 FastAPI 上设计 RESTfull API 的优秀模板，其中有仅使用 Pytest 编写的自动测试示例