Async fixtures with pytest

Question

How do I define async fixtures and use them in async tests?

The following code, all in the same file, fails miserably. Is the fixture called plainly by the test runn

Answer 1

You only need to mark your tests as async

@pytest.mark.asyncio
async def test_app(create_x, auth):
    api_client, x_id = create_x
    resp = await api_client.get(f'my_res/{x_id}', headers=auth)
    assert resp.status == web.HTTPOk.status_code

This tells pytest to run the test inside an event loop rather than calling it directly.

The fixtures can be marked as normal

@pytest.fixture
async def create_x(api_client):
    x_id = await add_x(api_client)
    return api_client, x_id

Answer 2

Coroutine functions are not natively supported by PyTest, so you need to install additional framework for it

• pytest-aiohttp
• pytest-asyncio
• pytest-trio
• pytest-tornasync

If you use pytest-aiohttp, your problem solves in this way

import asyncio
import pytest

from app import db


url = 'postgresql://postgres:postgres@localhost:5432'


@pytest.fixture(scope='session')
def loop():
    return asyncio.get_event_loop()


@pytest.fixture(scope='session', autouse=True)
async def prepare_db(loop):
    async with db.with_bind(f'{url}/postgres') as engine:
        await engine.status(db.text('CREATE DATABASE test_db'))

    await db.set_bind(f'{url}/test_db')
    await db.gino.create_all()

    yield
    await db.bind.close()

    async with db.with_bind(f'{url}/postgres') as engine:
        await engine.status(db.text('DROP DATABASE test_db'))

Main idea is using synchronous loop-fixture which will be used by async fixtures