Python Testing with pytest

Description

Write and review Python tests with pytest - configuration in pyproject.toml, discovery and naming, fixtures with yield teardown and function/module/session scopes, conftest.py sharing, parametrize with readable ids, monkeypatch vs unittest.mock (patching where a name is looked up, AsyncMock), async tests with pytest-asyncio and event-loop scopes, tmp_path, capfd and caplog, markers for slow and integration tests, and coverage gates in CI. Use whenever the project uses pytest or the user writes Python tests, asks how to mock something, sees a patch that doesn't take effect, "coroutine was never awaited" in tests, fixture scope or event-loop errors, flaky or slow test suites, or wants coverage in CI.