# Rut Testing > Use rut test runner instead of pytest for running Python unittest tests. Use when this capability is needed. - Skill: `tomevault-io/rut-testing` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/rut-testing` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/rut-testing/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/rut-testing --- # RUT Test Runner Use `rut` instead of `pytest` for running tests in this project. ## CLI Options | Option | Short | Description | |--------|-------|-------------| | `--keyword` | `-k` | Only run tests matching keyword | | `--exitfirst` | `-x` | Exit on first failure | | `--capture` | `-s` | Disable output capturing (show prints) | | `--changed` | `-c` | Only run tests affected by file changes | | `--dry-run` | | List tests without running them | | `--verbose` | `-v` | Show test names instead of dots | | `--cov` | | Run with code coverage | | `--alpha` | `-a` | Sort tests alphabetically | | `--no-color` | | Disable colored output | | `--debug` | | Show dependency graph and changed modules | | `--version` | `-V` | Show version and exit | | `--test-base-dir` | | Base directory for conftest.py discovery | | `path` | | Path to tests (default: `tests`) | ## Running Tests Workflow **Always use `rut -c` by default** to only run tests affected by file changes. 1. Run affected tests: `rut -c` 2. Run specific test: `rut -k "test_transfer"` 3. On failure, use `-x` to stop at first failure: `rut -x -k "test_transfer"` 4. Run linters: `ruff check` and `import_deps --check` (if available) 5. Debug with `-s` to see print output: `rut -s -k "failing_test"` ## Writing Tests Principles - Don't change app code and tests simultaneously - change one at a time - Follow TDD - make tests fail first, then make them pass - Don't mock the database - only mock external services requiring internet - No for-loops or if-clauses in tests - tests should be linear and explicit - Goal: exercise code, test complex logic, fix bugs (not 100% coverage) ## Quick Reference - Tests use `unittest.TestCase` (sync) or `unittest.IsolatedAsyncioTestCase` (async) - Cache stored in `.rut_cache/` - updated only after successful runs - For configuration, conftest hooks, and examples, see [REFERENCE.md](REFERENCE.md) --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/schettino72) — claim your Tome and manage your conversions.