Testing aiohttp & mongo with pytest

I have a simple coroutine register that accepts login and password as post arguments, then it goes into the database and so on. The problem I have is that I do not know how to test the coroutine.

I followed examples from https://aiohttp.readthedocs.io/en/latest/testing.html.

And everything seemed easy until I started writing tests myself.

Code for test_register.py

from main import make_app
pytest_plugins = 'aiohttp.pytest_plugin'


@pytest.fixture
def cli(loop, test_client):
    return loop.run_until_complete(test_client(make_app))

async def test_register(cli):
    resp = await cli.post('/register', data={'login': 'emil', 'password': 'qwerty'})
    assert resp.status == 200
    text = await resp.text()

And register.py

from settings import db

async def register(request):
    post_data = await request.post()
    print('Gotta: ', post_data)
    login, password = post_data['login'], post_data['password']
    matches = await db.users.find({'login': login}).count()
    ...

main.py

from aiohttp import web
from routes import routes


def make_app(loop=None):
    app = web.Application(loop=loop)
    for route in routes:
        app.router.add_route(route.method, route.url, route.handler)
    return app


def main():
    web.run_app(make_app())


if __name__ == "__main__":
    main()

settings.py

from motor.motor_asyncio import AsyncIOMotorClient
DBNAME = 'testdb'
db = AsyncIOMotorClient()[DBNAME]

And then I ran py.test test_register.py and it got stuck on database operation matches = await db.users.find({'login': login}).count()

Solution

The root of your problem is global variable usage.

I suggest the following changes:

from aiohttp import web
from motor.motor_asyncio import AsyncIOMotorClient
from routes import routes

def make_app(loop=None):
    app = web.Application(loop=loop)
    DBNAME = 'testdb'
    mongo = AsyncIOMotorClient(io_loop=loop)
    db = mongo[DBNAME]
    app['db'] = db

    async def cleanup(app):
        mongo.close()

    app.on_cleanup.append(cleanup)

    for route in routes:
        app.router.add_route(route.method, route.url, route.handler)
    return app

async def register(request):
    post_data = await request.post()
    print('Gotta: ', post_data)
    login, password = post_data['login'], post_data['password']
    matches = await request.app['db'].users.find(
        {'login': login}).count()
    ...

Pushing common-used objects into application's storage is an appreciated way for handling database connections etc.