# Tdd Cycle

> Run complete TDD red-green-refactor cycle for a test Use when this capability is needed.

- Skill: `tomevault-io/tdd-cycle` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/tdd-cycle`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/tdd-cycle/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/tdd-cycle

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# TDD Cycle

Execute a complete Red -> Green -> Refactor cycle.

## Workflow

### 1. Verify Task File

Check for `.tasks/YYYY-MM-DD-*.md`. If missing, create one before proceeding.

### 2. RED — Write Failing Test

1. Show test inventory from task file, ask which test to implement
2. Study patterns from existing tests (unit -> `assert_test.sh`, doubles -> `doubles_test.sh`)
3. Write the failing test following Arrange-Act-Assert
4. Run: `./bashunit path/to/test.sh` — **must fail**
5. Verify failure is for the RIGHT reason (not syntax error or wrong setup)
6. Update task file: current red bar + logbook entry

### 3. GREEN — Make It Pass

1. Write **minimal** code in `src/` — only enough for THIS test
2. Run: `./bashunit path/to/test.sh` — **must pass**
3. Update task file: check off test + logbook entry

### 4. REFACTOR — Improve Code

1. Improve readability, naming, extract duplication — no behavior changes
2. Run tests after each change
3. Quality checks: `make sa && make lint && shfmt -w .`
4. Full suite: `./bashunit tests/`
5. Update task file with refactoring notes

### 5. Next Test

Show updated test inventory. Ask if continuing or done.

## Critical Rules

- **Never skip RED** — always verify test fails first
- **Minimal code in GREEN** — resist feature creep
- **All tests green during REFACTOR** — revert if broken
- **Update task file** after each phase

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<!-- tomevault:4.0:skill_md:2026-04-11 -->