为什么我会收到重复收集的 pytest anyio 测试

Question

背景

我正在使用 pytest 和 asyncio 为 MongoDB + FastAPI 后端编写测试。我在设置时遇到了许多不同的问题，例如

Event Loop Close

、

Task Pending <name=

和

AttributeError: 'async_generator' object has no attribute 'post'

。但我最终得到了这个有效的设置。所以这是一个最小的可重复示例。我很抱歉这么长，但我认为有必要了解整个背景

项目设置

main.py

：

from fastapi import FastAPI
from contextlib import asynccontextmanager
from app.database import close_mongo_connection, connect_to_mongo
from app.routes.auth_routes import router as auth_router
app = FastAPI()

@asynccontextmanager
async def lifespan(app: FastAPI):
    print("Connecting to MongoDB")
    await connect_to_mongo()
    yield
    print("Closing connection to MongoDB")
    await close_mongo_connection()

app.router.lifespan_context = lifespan

app.include_router(auth_router, prefix="/auth", tags=["auth"])

database.py

：

import os
from motor.motor_asyncio import AsyncIOMotorClient
from app.config import DATABASE_NAME, MONGO_DETAILS, TEST_DATABASE_NAME

client: AsyncIOMotorClient = None
db = None

async def connect_to_mongo():
    global client, db
    client = AsyncIOMotorClient(MONGO_DETAILS)
    if os.getenv("IS_TESTING") == "True":
        db = client[TEST_DATABASE_NAME]
    else:
        db = client[DATABASE_NAME]

async def close_mongo_connection():
    if os.getenv("IS_TESTING") == "True":
        await client.drop_database(TEST_DATABASE_NAME)
    client.close()
    print("Disconnected from MongoDB")

async def get_database():
    if db is None:
        await connect_to_mongo()
    return db

routes/auth_routes

：

from app.database import get_database
from fastapi import APIRouter
router = APIRouter()

async def create_user(user: UserCreate, db) -> UserModel:
    users_collection = db["users"]
    user_dict = user.model_dump()
    user_dict["hashed_password"] = get_password_hash(user_dict.pop("password"))
    return await users_collection.insert_one(user_dict)

@router.post("/register", response_model=UserModel)
async def register_user(user: UserCreate, db=Depends(get_database)):
    print("GET DB", db)
    db_user = await create_user(user, db)
    return db_user

（相关）安装的库：

anyio             4.4.0
httpcore          1.0.5
httptools         0.6.1
httpx             0.27.0
motor             3.4.0
pip               24.0
pytest            8.2.2
pytest-asyncio    0.23.7
python-dotenv     1.0.1

测试设置

tests/conftest.py

：

import pytest
from app.database import close_mongo_connection, connect_to_mongo

@pytest.fixture(scope="module", autouse=True)
async def setup_and_teardown():
    await connect_to_mongo()
    print("This function does not run, but the testing setup does not work without it")
    yield
    await close_mongo_connection()

tests/test_auth.py

：

import pytest
from httpx import AsyncClient, ASGITransport
from app.main import app
from app.database import connect_to_mongo, close_mongo_connection

@pytest.fixture(scope="module", autouse=True)
async def setup_and_teardown():
    await connect_to_mongo()
    print("this runs")
    yield
    await close_mongo_connection()

client = AsyncClient(transport=ASGITransport(app=app), base_url="http://testserver")

@pytest.mark.anyio
async def test_register_user():
    user_data = {
        "email": "[email protected]",
        "password": "password123",
    }
    response = await client.post("/auth/register", json=user_data)

问题

功能良好，测试行为正确。但每当我输入

pytest

命令时，都会收集双倍的测试数量。例如，在我提供的示例设置中，pytest 将收集 2 个测试，并且它们都会执行（可以通过创建 2 个用户来验证）。这适用于多个文件中的所有测试。在我的完整设置中，我有 6 个测试，但它始终收集并执行 12 个测试。为什么会发生这种情况以及如何解决它。

Answer 1

我想这会解决你的问题：

@pytest.fixture
def anyio_backend():
    return 'asyncio'

我从官方文档中获取它，

通过这种方式，AnyIO 仅使用 asyncio 进行测试。