pytest-asyncio-cooperative 0.16.0

Run all your asynchronous tests cooperatively.

Use asyncio (cooperative multitasking) to run your I/O bound test suite efficiently and quickly.

import asyncio

import pytest

@pytest.mark.asyncio_cooperative
async def test_a():
    await asyncio.sleep(2)


@pytest.mark.asyncio_cooperative
async def test_b():
    await asyncio.sleep(2)

========== 2 passed in 2.05 seconds ==========

Quickstart

pip install pytest-asyncio-cooperative

Compatibility

pytest-asyncio is NOT compatible with this plugin. Please uninstall pytest-asyncio or pass this flag to pytest -p no:asyncio

Fixtures

It’s recommended that async tests use async fixtures.

import asyncio
import pytest


@pytest.fixture
async def my_fixture():
    await asyncio.sleep(2)
    yield "XXX"
    await asyncio.sleep(2)


@pytest.mark.asyncio_cooperative
async def test_a(my_fixture):
    await asyncio.sleep(2)
    assert my_fixture == "XXX"

Goals

• Reduce the total run time of I/O bound test suites via cooperative multitasking

• Reduce system resource usage via cooperative multitasking

Pros

• An I/O bound test suite will run faster (ie. individual tests will take just as long. The total runtime of the entire test suite will be faster)

• An I/O bound test suite will use less system resources (ie. only a single thread is used)

Cons

• All tests MUST be coroutines (ie. have the async keyword)

• Order of tests is not guaranteed (ie. some blocking operations might taken longer and affect the order of test results)

• Tests MUST be isolated from each other (ie. NO shared resources, NO mock.patch)

• There is NO parallelism, CPU bound tests will NOT get a performance benefit