# OpenStack oslotest — timeout moved from base class into a fixture

## Metadata

| Field | Value |
|---|---|
| Institute | Molodetz Institute — Research & Retrieval Division |
| Subject | async-pty-process-testing |
| Document type | Source Dossier |
| Tier | 1 |
| Source title | oslotest/timeout.py, and companion base.py commit |
| Source URL | https://gitea10.opendev.org:3081/x/deb-oslotest/src/branch/master/oslotest/timeout.py |
| Source publisher / author | OpenStack project (oslotest) |
| Source type | repository |
| Source date (published) | Unknown — not stated |
| Date researched | 2026-10-09 |
| Researched by | tai (agent), model: Claude Sonnet 5, on behalf of retoor |
| Research method | web search synthesis |
| Confidence | Medium |
| Status | Active |

## Summary

OpenStack's `oslotest` originally read a timeout value from an `OS_TEST_TIMEOUT` environment variable directly inside its base test class, then later moved that behavior into a separate, opt-in fixture (`fixtures.Timeout`) rather than something every test inherits unconditionally.

## Key findings

- The commit message for the change explicitly frames it as replacing inline base-class code that checked `OS_TEST_TIMEOUT` with a dedicated fixture, so tests opt into timeout behavior rather than being forced to inherit it.
- This is a structural decision about *where* configuration lives (base class vs. opt-in fixture), not a new timeout algorithm.

## Pros / strengths

- A real example of a mature test framework deliberately refactoring away from "everything lives in the base class" toward more granular, optional composition — relevant precedent for deciding how configurable a shared test base class should be.

## Cons / limitations / caveats

- Only the timeout-related commit and file were reviewed; the broader `oslotest` fixture ecosystem and how widely this opt-in pattern is used elsewhere in the project were not examined.

## Relevance to tai

Informed the decision to make `timeout` a per-`TestCase` class attribute (with a sensible default, overridable per test and via the `--timeout` CLI flag in `main_cli`) rather than a single hardcoded constant baked into the framework's execution loop — closer in spirit to oslotest's "configurable, not force-inherited" approach than to a one-size-fits-all timeout.

## Changelog

| Date | Change |
|---|---|
| 2026-10-09 | Initial dossier created. |