# Test Driven Development

> Use when implementing a feature, fixing a bug, or changing behavior in Cursor and you want a disciplined red-green-refactor workflow.

- Skill: `6bnbn/test-driven-development` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add 6bnbn/test-driven-development`
- Raw SKILL.md: https://api.skillmd.com/api/skills/6bnbn/test-driven-development/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: 6bnbn (https://skillmd.com/u/6bnbn)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/6bnbn/test-driven-development

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# Test-Driven Development

## Goal
Write the failing test first, then the smallest implementation that makes it pass.

## Workflow
1. Write one failing test for one behavior.
2. Run it and confirm it fails for the right reason.
3. Implement the minimal code needed to pass.
4. Re-run the test and nearby checks.
5. Refactor while keeping everything green.
6. Repeat for the next behavior.

## Rules
- No production code before a failing test unless the user explicitly asks to skip TDD.
- Keep tests focused on behavior, not incidental implementation details.
- Prefer real code paths over heavy mocking.
- If the test passes immediately, you are probably testing existing behavior or the wrong thing.
- Use `verification-before-completion` before claiming the bug or feature is finished.

## Good Test Qualities
- one behavior
- clear name
- obvious expected outcome
- minimal setup
- catches the intended regression