test-driven-development

What problem does it solve? Code written before tests often ships unverified, and tests written after implementation pass immediately without proving they test the right behavior. This Skill enforces a strict test-first discipline so every feature and bugfix is backed by a test that was watched failing before any production code exists. ## Core Features & Use Cases - Red-Green-Refactor Cycle: Guides writing one failing test, verifying it fails for the right reason, writing minimal code to pass, then refactoring while staying green. - Rationalization Countermeasures: Provides a table of common excuses ("too simple to test", "I'll test after") with rebuttals, plus red flags that signal you must delete code and start over. - Testing Anti-Patterns Reference: Ships a references file covering mock-behavior testing, test-only production methods, and mocking without understanding dependencies. - Use Case: When fixing a bug where an empty email is accepted, write a failing test asserting the rejection error, watch it fail, implement the minimal validation, and confirm the full suite passes. ## Quick Start Ask the AI to implement a new feature or bugfix using strict test-driven development, writing the failing test before any production code.