使用 Motor AsyncIO 和 Pytest 测试 MongoDB 功能

Question

所以我正在尝试编写几个测试来测试我使用异步 MongoDB 连接的函数。为了连接到 MongoDB，我使用 Motor 和 asyncio。我需要帮助模拟电机连接。

我的代码：

公地.py

mongo = None

黑名单.py

import commons

class Blacklist(object):
    async def check_if_blacklisted(self, word: str):
        blacklisted = False
        if await commons.mongo.dbtest.blacklist.find_one({'word': word}):
            blacklisted = True
        return blacklisted

主文件

import asyncio
from blacklist import Blacklist
from motor.motor_asyncio import AsyncIOMotorClient
import commons

async def run():
    commons.mongo = AsyncIOMotorClient("mongodb://localhost", io_loop=asyncio.get_event_loop())
    blacklist_checker = Blacklist()
    result = await blacklist_checker.check_if_blacklisted(word="should_be_false")
    print(result)
    # > False

    result = await blacklist_checker.check_if_blacklisted(word="should_be_true")
    print(result)
    # > True

loop = asyncio.get_event_loop()
loop.run_until_complete(run())
loop.close()

我现在想通过模拟电机连接来测试 blacklist.py，但我似乎无法正常运行测试。以下是我尝试过的代码：

test_blacklist.py

import pytest
from blacklist import Blacklist

class TestBlacklist(object):

@pytest.fixture
async def motor(self, event_loop):
    # I know I'm not mocking the Motor Connection here, 
    # but just wanted to show you the output using this fixture.
    commons.mongo = motor.motor_asyncio.AsyncIOMotorClient(io_loop=event_loop)
    yield commons.mongo
    commons.mongo.close()

@pytest.mark.asyncio
async def test_check_if_blacklisted(self):
    blacklist_checker = Blacklist()
    blacklisted = await blacklist_checker.check_if_blacklisted(word="should_be_false")
    assert blacklisted == False
    # > AttributeError: 'NoneType' object has no attribute 'blacklist'

pytest-mongodb：

import pytest
from unittest.mock import patch
from blacklist import Blacklist

class TestBlacklist(object):

    @pytest.mark.asyncio
    async def test_check_if_blacklisted(self, mongodb):
        with patch("blacklist.commons.mongo") as db:
            db = mongodb
            blacklist_checker = Blacklist()
            blacklisted = await blacklist_checker.check_if_blacklisted(word="should_be_false")
        assert blacklisted == False
        # > TypeError: object MagicMock can't be used in 'await' expression

我尝试在线搜索，但找不到合适的线程来帮助我在模拟异步电机连接时执行测试。此外，如果您认为我的测试方向不正确，请告诉我，因为我是编写测试的新手，尤其是异步数据库连接。

注意： blacklist.py 有各种需要 MongoDB 功能的函数，所以如果在我的 test_blacklist.py 中我可以只初始化 commons.mongo 一次并且所有后续测试都使用它，那就太好了。

Answer 1

您可以使用pytest-async-mongodb模拟异步 MongoDB 数据库，但请记住它已经过时并且存在依赖项错误，因此您必须按如下所示修复依赖项版本：

mongomock==3.12.0
pyyaml==3.13
pytest-asyncio==0.10.0
pytest==3.6.4

使用pytest-async-mongodb，您可以通过添加名为async_mongodb的参数来在测试中获取模拟数据库。我将向您提供代码和结构。

project
  -app
    __init__.py
    blacklist.py
    commons.py
  -test
    -fixtures
      blacklist.json
    __init__.py
    test_blacklist.py
  main.py
  pytest.ini

主要.py

import asyncio
from app.blacklist import Blacklist
from app.commons import get_database, set_client
from motor.motor_asyncio import AsyncIOMotorClient


async def run():
    set_client(
        AsyncIOMotorClient("mongodb://localhost", io_loop=asyncio.get_event_loop())
    )
    db = await get_database()
    blacklist_checker = Blacklist()
    result = await blacklist_checker.check_if_blacklisted(db, word="should_be_false")
    print(result)
    # > False

    result = await blacklist_checker.check_if_blacklisted(db, word="should_be_true")
    print(result)
    # > True


loop = asyncio.get_event_loop()
loop.run_until_complete(run())
loop.close()

黑名单.py

from motor.motor_asyncio import AsyncIOMotorDatabase


class Blacklist(object):
    async def check_if_blacklisted(self, db: AsyncIOMotorDatabase, word: str):
        blacklisted = False
        if await db.blacklist.find_one({"word": word}):
            blacklisted = True
        return blacklisted

公共资源.py

from motor.motor_asyncio import AsyncIOMotorClient, AsyncIOMotorDatabase


class DataBase:
    client: AsyncIOMotorClient = None


db = DataBase()


async def get_database() -> AsyncIOMotorDatabase:
    return db.client["dbtest"]


def set_client(client):
    db.client = client

test_blacklist.py

import pytest
from app import blacklist


@pytest.mark.asyncio
async def test_should_be_false(async_mongodb):
    blacklist_checker = blacklist.Blacklist()
    blacklisted = await blacklist_checker.check_if_blacklisted(
        async_mongodb, word="should_be_false"
    )
    assert blacklisted == False


@pytest.mark.asyncio
async def test_should_be_true(async_mongodb):
    blacklist_checker = blacklist.Blacklist()
    blacklisted = await blacklist_checker.check_if_blacklisted(
        async_mongodb, word="should_be_true"
    )
    assert blacklisted == True

pytest.ini

[pytest]
async_mongodb_fixture_dir =
  test/fixtures

async_mongodb_fixtures =
  blacklist

黑名单.json

[
    {
      "_id": {"$oid": "60511d158f80a8d34986e2b0"},
      "word" : "should_be_true"
    }
]

固定装置也可以是.yaml，并且可以定义您想要的数量。请阅读软件包文档以获取更多信息。

由于它已经过时，我创建了一个分支来更新它并使用新功能对其进行改进。我们邀请您查看并根据需要使用它。