py-testing-asynclisted

# Python Async Testing ## Problem Statement Async testing requires specific patterns. pytest-asyncio has modes that affect behavior. Database tests need isolation. Mocking async functions differs from sync. Get these wrong and tests are flaky or don't catch bugs. --- ## Pattern: pytest-asyncio Configuration **Problem:** Pytest needs configuration for async tests. ```toml # pyproject.toml [tool.pytest.ini_options] asyncio_mode = "strict" # Requires explicit @pytest.mark.asyncio # OR asyncio_mode = "auto" # All async tests run automatically ``` ```python import pytest # With asyncio_mode = "strict" (this codebase) @pytest.mark.asyncio async def test_something(): result = await some_async_function() assert result == expected # Without the marker = test won't run as async! ``` --- ## Pattern: Async Fixtures **Problem:** Fixtures that provide async resources need specific handling. ```python import pytest from sqlalchemy.ext.asyncio import AsyncSession # ✅ CORRECT: Async fixture for session @pytest.fixture async def session() -> AsyncGenerator[AsyncSession, None]: async with async_session() as session: yield session await session.rollback() # Clean up after test # ✅ CORRECT: Async fixture for test data @pytest.fixture async def test_user(session: AsyncSession) -> User: user = User(email="test@example.com", hashed_password="...") session.add(user) await session.commit() await session.refresh(user) return user # ✅