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Pytest plugin for testing async python code

Project description


pytest-aio – Is a simple pytest plugin for testing any async python code

Tests Status PYPI Version Python Versions


  • Supports all most popular async python libraries: Asyncio, Trio and Curio

  • Automatically run your async tests

  • Works with contextvars correctly (supports it for async/sync fixtures)

  • Supports trio-asyncio


  • python >= 3.9


pytest-aio should be installed using pip:

pip install pytest-aio

optionally extras are available:

pip install pytest-aio[curio,trio]


When installed the plugin runs all your async test functions/fixtures.

async def test_async():
    assert True

No need to mark your async tests. Just run pytest as is.

Async fixtures for sync tests

If you plan use async fixtures for sync tests, please ensure you have to include aiolib fixture:

# It's important to add aiolib fixture here
def test_with_async_fixtures(async_fixture, aiolib):
    assert async_fixture == 'value from async fixture'

As an alternative, If you are doing the async fixtures yourself, you can add aiolib inside them:

async def async_fixture(aiolib):
    return 'value from async fixture'

# So for the test we don't need to implicity use `aiolib` anymore
def test_with_async_fixtures(async_fixture):
    assert async_fixture == 'value from async fixture'

Customize async libraries

By default each test function will be run with asyncio, trio, curio backends consistently (only if trio/curio are installed). But you can customise the libraries for all your tests creating the global fixture:

# Run all tests with Asyncio/Trio only
@pytest.fixture(params=['asyncio', 'trio'])
def aiolib(request):
    assert request.param

If you want to specify different options for the selected backend, you can do so by passing a tuple of (backend name, options dict):

    pytest.param(('asyncio', {'use_uvloop': False}), id='asyncio'),
    pytest.param(('asyncio', {'use_uvloop': True}), id='asyncio+uvloop'),
    pytest.param(('trio', {'trio_asyncio': True}), id='trio+asyncio'),
    pytest.param(('curio', {'debug': True}), id='curio'),
def aiolib(request):
    assert request.param

To set a specific backends for a single test only:

@pytest.mark.parametrize('aiolib', ['asyncio'])
async def only_with_asyncio():
    await asyncio.sleep(1)
    assert True


The plugin contains aiosleep fixture. It’s an equivalent to asyncio.sleep, trio.sleep, curio.sleep for current running library.

Bug tracker

If you have any suggestions, bug reports or annoyances please report them to the issue tracker at


Development of the project happens at:


Licensed under a MIT license.

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