What are the best practices for using pytest-asyncio?

What are the best practices for using pytest-asyncio?

When using pytest-asyncio, it's important to ensure that your tests are properly structured for asynchronous code. Here are some best practices:

1. Use the @pytest.mark.asyncio decorator to mark your test functions as asynchronous.
2. Avoid using asyncio.run() within your tests; instead, use the event loop provided by pytest-asyncio.
3. Keep your tests isolated and avoid shared state between tests to prevent flaky tests.

Can you give an example of an async test?

Sure! Here's a simple example of an async test using pytest-asyncio:

import pytest
import asyncio

async def fetch_data():
    await asyncio.sleep(1)
    return 'data'

@pytest.mark.asyncio
async def test_fetch_data():
    result = await fetch_data()
    assert result == 'data'

What should I do if my tests are flaky?

Flaky tests can be frustrating. Here are some steps to troubleshoot:

1. Ensure that your tests are independent and do not rely on shared state.
2. Check for any race conditions in your async code.
3. Use pytest --maxfail=1 to stop after the first failure, which can help identify issues more quickly.

Are there any plugins that can help with async testing?

Yes, there are several plugins that can enhance your async testing experience with pytest. One popular plugin is pytest-asyncio, which provides support for testing asyncio code. Additionally, you might consider pytest-timeout to set timeouts for your tests, helping to catch any hanging async calls.