What problem does it solve? Code written before tests often ships with unverified behavior, hidden bugs, and tests that pass immediately without proving anything. This Skill enforces a strict test-driven development discipline so every line of production code is backed by a failing test written first. ## Core Features & Use Cases - Red-Green-Refactor Cycle: Guides writing a failing test, verifying it fails for the right reason, implementing minimal code, and refactoring while staying green. - Anti-Rationalization Rules: Counters common excuses like "I'll test after" or "deleting work is wasteful" with concrete reasoning and mandatory restart rules. - Testing Anti-Pattern Reference: Covers pitfalls like testing mock behavior, test-only methods in production classes, incomplete mocks, and HTTP/mock library mismatches (requests+responses, httpx+respx, aiohttp+aioresponses). - Use Case: When fixing a bug where empty emails are 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 pass it.
