What problem does it solve? Writing code before tests leads to unverified implementations, biased tests written after the fact, 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 any production code exists. ## 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 implementation, and passes after minimal code is written. - Rationalization Detection: Lists common excuses for skipping TDD (such as "too simple to test" or "I'll test after") with concrete rebuttals, plus red flags that trigger a restart of the cycle. - Testing Anti-Pattern Reference: A companion reference covers testing mock behavior, test-only methods in production classes, incomplete mocks, and mocking without understanding dependencies. - Use Case: When fixing a bug where an empty email is accepted, write a failing test asserting the rejection, watch it fail, implement the minimal validation, verify it passes, then refactor. ## 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.
