pytest testing method

Write the contract under test as independent expectations first, then choose fixtures, parametrization and stubs; test count and coverage are no substitute for behavioural correctness.

Inputs and capability

Take the target module/behaviour, allowed files and external boundaries, the actual Python/pytest/plugin versions, the existing test entry, async mode, fixture ownership, node resources and how results are counted. Without pytest, cases can be written and separable standard-library logic executed, but this cannot be called a pytest pass; without pytest-mock use unittest.mock/monkeypatch, without xdist run serially, and install neither automatically.

Without an async plugin, do not treat a bare async def as executed: being collected or skipped does not prove the function body ran. With no plugin and a test that fully owns its event loop, asyncio.run may be used inside an ordinary test; with loop-bound fixtures or an existing async framework, settle the compatible mode first and do not start a nested event loop.

Method routing

1. Write input, action, output/error/side effect, and parametrize with explicit expectations and readable IDs. A counterexample must be able to expose the target defect; do not fix assertions to fit a wrong implementation.
2. Follow Fixtures and async to decide scope, resource acquisition/release, patch boundary, async mode and cancellation. Use existing fixtures where possible; do not build a large autouse fixture for uniformity.
3. For external integration or parallel runs, follow Parallelism and integration for independent data, worker/attempt identity and cleanup; external calls run only in a permitted isolated environment.
4. Run the affected cases first and confirm the actually collected set, that the test bodies executed and the final state of cleanup; run related regressions afterwards when needed. Record failed/error/skip/xfail/xpass/not run; exit code 0 cannot stand in for all expectations passing.
5. Use pytest evidence to deliver scope, versions, plugins, original failures and re-verification; do not rerun unrelated tests or push TDD/coverage thresholds without need.

Failure and continuation

Tell apart collection, fixture setup, test call and teardown. A setup failure may not have reached yield yet; resources already acquired successfully must be released. Keep both assertion failures and cleanup failures; a teardown failure must not overwrite the first business error. An unavailable dependency blocks only the corresponding integration; pure-logic checks may continue.

On continuation, verify the candidate, selected set, execution handles, exclusive resources and completed results; do not assume the old process has stopped. When resources are insufficient, change concurrency first; do not skip required cases.

Resource suggestion: mechanical execution uses low/low; routine fixtures/parametrization use normal/medium; event loop, shared state and concurrency failures use normal/high. Grade words map to actual execution configuration through the project resource mapping.

Normal example: tmp_path per case, the real function under test, a stub at the HTTP boundary; without xdist, run the same set serially. Counterexample: the whole suite sharing a fixed temp.txt, counting a skipped async test as passed, rerunning until green and then deleting the first-run failure.

Wrap-up cleanup: processes, containers, temporary files and test data started outside fixtures are reclaimed after the session ends; built-in temporary directories such as tmp_path follow pytest's own retention policy, and the global basetemp is not cleaned by hand. Follow the local resource cleanup rule of task-implementation: register identity on creation, reclaim only objects registered this run at wrap-up, write evidence to be kept and cleanup failures into the receipt, and use no global cleanup commands.

Sources

1. Pinned source: EC08 python-testing.
2. Adopted the fixture/yield, parametrization, mock/autospec, async and temporary-resource topics; cleanup on setup failure, the strict/auto distinction, worker isolation and the no-plugin path are own-authored for this package. Dropped mandatory TDD for every task, fixed coverage, shared temporary files, automatic plugin installation and undeclared external calls.
3. License: shipped with the package as LICENSE-EC.txt (EC, MIT); library-wide third-party summary in the root THIRD_PARTY_NOTICES.md. Copy the license file along when copying this package alone.