What is the 'Iron Law' in this TDD skill?

The Iron Law mandates that no production code should be written until a failing test exists, ensuring all behavior is systematically verified.

What happens if I write implementation code before the test?

According to the skill's protocols, any code written before its corresponding test should be deleted and rewritten to ensure implementation is strictly driven by requirements.

Can I use this TDD skill for fixing bugs?

Yes. The skill requires writing a reproduction test that fails before implementing the fix, providing proof that the bug is resolved once the test passes.

Why does this skill insist on watching a test fail?

If you don't see a test fail (the RED phase), you cannot be certain the test is actually testing the right behavior or that it has the power to catch a bug.

Does this skill help with code refactoring?

Yes. It guides you through the Refactor phase only after achieving a passing state, ensuring that code cleanup never breaks existing functionality.

Test-Driven Development (TDD)

Name: Test-Driven Development (TDD)
Author: kivilaid

bykivilaid

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Security & Testing

Enforces a strict Red-Green-Refactor workflow to ensure high-quality, verified code through test-first implementation.

This skill equips Claude with the rigorous discipline of Test-Driven Development, preventing the creation of production code until a failing test has been established. It follows the 'Iron Law' of TDD, guiding users through the cycle of writing minimal tests, verifying failures, implementing passing code, and refactoring while maintaining 'green' status. By prioritizing behavior verification over implementation guesses, it significantly reduces technical debt and ensures that every line of code serves a documented, tested purpose.

Key Features

01Detailed validation checklist for bug fixes and new features

026 GitHub stars

03Enforcement of minimal code production to achieve GREEN status

04Systematic refactoring guidance to clean code without breaking functionality

05Strict adherence to the Red-Green-Refactor cycle

06Mandatory verification of test failure (RED) before implementation

Use Cases

01Safely refactoring legacy codebases by establishing a test safety net

02Building new software features with high confidence and minimal regressions

03Fixing complex bugs by reproducing them with failing tests first

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add kivilaid/plugin-marketplace test-driven-development

For use in Claude.ai and ChatGPT

Download Skill