# Tdd

> Test-Driven Development enforcement skill - write tests first, always Use when this capability is needed.

- Skill: `tomevault-io/tdd-33` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/tdd-33`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/tdd-33/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-33

---


# TDD Mode

[TDD MODE ACTIVATED]

## The Iron Law

**NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST**

Write code before test? DELETE IT. Start over. No exceptions.

## Red-Green-Refactor Cycle

### 1. RED: Write Failing Test
- Write test for the NEXT piece of functionality
- Run test - MUST FAIL
- If it passes, your test is wrong

### 2. GREEN: Minimal Implementation
- Write ONLY enough code to pass the test
- No extras. No "while I'm here."
- Run test - MUST PASS

### 3. REFACTOR: Clean Up
- Improve code quality
- Run tests after EVERY change
- Must stay green

### 4. REPEAT
- Next failing test
- Continue cycle

## Enforcement Rules

| If You See | Action |
|------------|--------|
| Code written before test | STOP. Delete code. Write test first. |
| Test passes on first run | Test is wrong. Fix it to fail first. |
| Multiple features in one cycle | STOP. One test, one feature. |
| Skipping refactor | Go back. Clean up before next feature. |

## Commands

Before each implementation:
```bash
npm test  # Should have ONE new failure
```

After implementation:
```bash
npm test  # New test should pass, all others still pass
```

## Output Format

When guiding TDD:

```
## TDD Cycle: [Feature Name]

### RED Phase
Test: [test code]
Expected failure: [what error you expect]
Actual: [run result showing failure]

### GREEN Phase
Implementation: [minimal code]
Result: [run result showing pass]

### REFACTOR Phase
Changes: [what was cleaned up]
Result: [tests still pass]
```

**Remember:** The discipline IS the value. Shortcuts destroy the benefit.

---
> Converted and distributed by [TomeVault](https://tomevault.io/claim/mazenyassergithub) — claim your Tome and manage your conversions.
<!-- tomevault:4.0:skill_md:2026-04-13 -->