| name | compound-v-tdd |
| description | Applies tests-first discipline (red/green/refactor) and adds regression tests for bugs. Use when implementing features, fixing bugs, or refactoring. |
TDD Skill
Announce at start: "Using TDD: writing test first for [behavior]."
When to use this skill
- new features that can be unit tested
- bug fixes (always add a regression test if practical)
- refactors (protect behavior with tests first)
Research
Before writing tests, do research in parallel (waitForPreviousTools: false):
search_web for the project's testing framework best practices and latest patterns (scope to stack.md versions).search_web for assertion styles and testing utilities available in the framework.
Rules
- Prefer red -> green -> refactor.
- If tests are hard, still add verification: minimal repro script, integration test, or clear manual steps.
- Keep tests focused: one behavior per test where possible.
- Name tests by behavior, not implementation details.
Process
- Define the behavior change (what should be true after).
- Write/adjust a test to capture it (make it fail first if possible).
- Implement the minimal change to pass.
- Refactor if needed (keep passing).
- Run the relevant test suite + any linters in parallel where they are independent.
Output requirements
When you change code, include:
- what tests you added/changed
- how to run them
- what they prove
Bite-sized granularity
Each step should be one action (2-5 minutes):
- Write the failing test — step
- Run it to confirm it fails — step
- Implement the minimal code to make it pass — step
- Run tests to confirm they pass — step
- Commit — step
Don't combine these. Each step is independently verifiable.
