Test, lint, and format ReVision

CI (.github/workflows/ci.yml) runs ruff check, ruff format --check, and pytest on Python 3.11–3.13, plus a Docker build. Match it locally before committing.

Commands

pytest                # test suite (config in pyproject.toml: testpaths=tests, pythonpath=src)
ruff check .          # lint: rules E, F, I, UP, B, SIM, line length 100
ruff format .         # auto-format (CI runs `ruff format --check`)

In some environments pytest/ruff are standalone binaries, not in the interpreter's site-packages. If python -m pytest says "No module named pytest", call pytest / ruff directly.

Test layout

Tests under tests/ mirror the module they cover (server.py → test_server.py):

• test_config.py — Config.from_env() and env-var parsing.
• test_anthropic_client.py — mocks urllib.request.urlopen; no network.
• test_ratelimit.py — limiter with a monkeypatched clock.
• test_server.py — runs a live server on port 0 with a fake injected client.

Key testing seam

create_server(config, client=...) accepts an injected AnthropicClient, so test_server.py runs a real server against a fake client with no network. Preserve this seam when touching server.py — don't hardcode client construction into the request path.

Before committing

1. ruff format .
2. ruff check .
3. pytest

Add a test alongside any behavior change, mirroring the module you touched. Keep the backend dependency-free (stdlib only); pytest/ruff are dev-only.