pytest-asyncio-cooperative 0.12.0

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

Known Issues

Synchronous tests fail to run when async tests fail

Async tests are run BEFORE synchronous tests. If an async test fails then synchronous tests will NOT run. Therefore the synchronous tests will not report to have passed or failed.