When should I use the TDD skill?

You should use it for all new features, bug fixes, and refactoring. Exceptions are only made for throwaway prototypes, generated code, or configuration files.

Can this skill help fix bugs in existing code?

Yes. It requires writing a failing test that reproduces the bug before any fix is implemented, ensuring the bug is truly understood and won't regress.

How does this skill handle the 'Refactor' phase?

After achieving a 'Green' state (passing test), the skill guides you to clean up duplication and improve names without adding new behavior, ensuring the test remains passing.

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

The Iron Law states that no production code should be written without a failing test first. If code is written before a test, the methodology requires deleting it and starting over.

Why does this skill mandate watching a test fail?

Watching a test fail (the Red phase) proves that the test is actually checking the intended behavior and that the failure is due to the missing feature rather than a configuration error.

Test-Driven Development (TDD)

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

bykivilaid

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セキュリティとテスト

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

概要

This skill equips Claude with the rigorous discipline of Test-Driven Development, ensuring that every piece of production code is preceded by a failing test. By prioritizing the Red-Green-Refactor cycle, it eliminates technical debt, prevents regressions, and guarantees that software behavior is verified through automated tests rather than ad-hoc manual checks. It is an essential tool for developers who prioritize code reliability, clear design, and long-term maintainability through disciplined engineering practices.

主な機能

Strict Red-Green-Refactor cycle enforcement
Comprehensive TDD checklists for features and bug fixes
Detection and correction of common TDD bypass rationalizations
6 GitHub stars
Mandatory verification of failing tests before implementation
Guidance on writing minimal, passing code to avoid over-engineering

ユースケース

Implementing new features with guaranteed automated test coverage
Reproducing and fixing bugs using regression-proof testing methods
Refactoring complex legacy code while maintaining functional integrity

概要

主な機能

Strict Red-Green-Refactor cycle enforcement
Comprehensive TDD checklists for features and bug fixes
Detection and correction of common TDD bypass rationalizations
6 GitHub stars
Mandatory verification of failing tests before implementation
Guidance on writing minimal, passing code to avoid over-engineering

ユースケース

Implementing new features with guaranteed automated test coverage
Reproducing and fixing bugs using regression-proof testing methods
Refactoring complex legacy code while maintaining functional integrity