What problem does it solve? Code written before tests often ships untested, and tests written after implementation pass immediately without proving they can catch bugs. This Skill enforces a strict test-first discipline so every behavior change is verified by a failing test before any production code exists. ## Core Features & Use Cases - Red-Green-Refactor Enforcement: Guides the full TDD cycle — write a failing test, verify it fails for the right reason, write minimal code to pass, then refactor 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 trigger deleting code and starting over. - Test Quality Rules: A companion reference defines how to write honest tests — name the production change each test catches, assert on real behavior instead of mocks, and run a mutation check before finishing. - Use Case: When fixing a bug where empty emails are accepted, write a failing test asserting the rejection error, watch it fail, implement the minimal validation, and confirm all tests pass. ## Quick Start Use the test-driven-development skill to implement this feature by writing a failing test first and following the red-green-refactor cycle.
