python-quality-tooling

# Python Quality Tooling

## Overview

Use ruff, ty, and pytest consistently through uv. Core principle: one repeatable quality gate across local and CI.

## Quick Reference

| Task | Command |
| --- | --- |
| Lint | `uv run ruff check` |
| Auto-fix | `uv run ruff check --fix` |
| Format | `uv run ruff format` |
| Type check | `uv run ty check` |
| Test | `uv run pytest` |
| Coverage | `uv run pytest --cov=src --cov-report=term-missing` |
| Full gate (prek) | `prek run -a` |
| Install git hooks (prek) | `prek install` |

## Workflow

- Install tools as dev deps (see `python-uv-project-setup`).
- Run all checks before commit.
- Keep CI aligned with local commands.
- If the repo uses prek, prefer `prek run -a` as the single quality gate.
- Pytest tests MUST be function-based (no class-based tests or `unittest.TestCase`).

## Example

Pre-merge gate:
```bash
uv run ruff check --fix
uv run ruff format
uv run ty check
uv run pytest --cov=src --cov-report=term-missing
```

## Common Mistakes

- Running tools outside uv (drifts from project env).
- Skipping `prek run -a` when a repo standardizes on prek.
- Running only one tool and calling it done.

## Red Flags

- Direct `ruff`/`pytest` invocations without `uv run`.
- Mixing `pre-commit` and `prek` commands in the same repo.
- Class-based pytest tests (`class Test*`) or `unittest.TestCase` usage.

## References

- `references/quality.md` - Full command set and CI example
- `references/quality.md` - Prek install and usage notes (prefer `uv tool install prek`)