What problem does it solve? Writing code before tests leads to unverified implementations, tests that pass immediately without proving anything, and regressions discovered only in production. This Skill enforces a strict test-first discipline so every behavior change is proven by a failing test before implementation begins. ## Core Features & Use Cases - Red-Green-Refactor Enforcement: Guides the full TDD cycle with mandatory verification that each test fails for the right reason before writing minimal code to pass it. - Rationalization Detection: Lists common excuses for skipping TDD ("too simple to test", "I'll test after") with concrete rebuttals and red flags that trigger a restart. - Testing Anti-Pattern Reference: Covers mock-behavior testing, test-only production methods, incomplete mocks, and over-mocking, with gate functions to catch each mistake. - Use Case: When fixing a bug like an empty email being accepted, write a failing test reproducing it, verify the failure, implement the minimal validation fix, and confirm all tests pass before refactoring. ## Quick Start Use the test-driven-development skill to implement this feature by writing a failing test first, then the minimal code to make it pass.
