Why is watching a test fail (RED) mandatory?

Watching a test fail proves that the test is actually checking the intended behavior. If a test passes immediately, it provides no evidence that your new code is working or necessary.

How does this skill handle refactoring?

Refactoring is only permitted during the 'Green' phase. Once a test passes, you can clean up the code while running tests frequently to ensure the behavior remains correct.

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

The Iron Law dictates that no production code can be written without a failing test existing first. If code is written before a test, it must be deleted and restarted.

Can I use this skill for bug fixes?

Yes. The skill requires you to write a failing test that reproduces the bug before writing any code to fix it, ensuring the bug is truly resolved and won't return.

Test-Driven Development (TDD)

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

byKrosebrook

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Security & Testing

Enforces a strict Red-Green-Refactor workflow to ensure all production code is verified by failing tests before implementation.

This skill transforms Claude into a disciplined TDD practitioner by mandating the 'Iron Law': no production code is written without a failing test first. It guides the AI through the rigorous Red-Green-Refactor cycle, ensuring that tests actually verify behavior by requiring a confirmed failure before any implementation. By following this systematic approach, the skill helps developers eliminate technical debt, prevent regressions, and create self-documenting codebases where every feature is backed by a purposeful test suite.

Key Features

01Strict enforcement of the Red-Green-Refactor development cycle

02Mandatory verification of test failure messages to avoid false positives

03Automated verification checklists for completing features and bug fixes

04Guidelines for avoiding common TDD rationalizations and shortcuts

051 GitHub stars

06Minimalist code implementation strategies to pass tests efficiently

Use Cases

01Reproducing and fixing bugs by creating regression tests first

02Refactoring complex logic while maintaining existing behavioral guarantees

03Building mission-critical features where reliability is the top priority

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add krosebrook/source-of-truth-monorepo test-driven-development

For use in Claude.ai and ChatGPT

Download Skill