What problem does it solve? Developers often write production code first and add tests later, or skip tests entirely for small fixes, leading to regressions, unverified bug fixes, and tests that validate mocks instead of real behavior. This Skill enforces a strict test-first discipline so every feature, bugfix, and refactor is backed by a failing test before any production code is written. ## Core Features & Use Cases - Iron Law Enforcement: Blocks production code changes until a failing test exists, with explicit red flags that trigger a stop-and-restart when violated. - Red-Green-Refactor Workflow: Guides the full cycle of writing a minimal failing test, implementing the simplest passing code, and refactoring without adding behavior. - Testing Anti-Pattern Reference: Documents five common anti-patterns (testing mock behavior, test-only production methods, mocking without understanding, incomplete mocks, tests as afterthought) with gate functions and fixes. - Use Case: While fixing a bug in an sp-debug workflow, write a failing test that reproduces the bug first, confirm the failure empirically, then implement the minimal fix and verify all tests pass. ## Quick Start Ask the AI to implement a new feature or fix a bug using test-driven development, writing a failing test before any production code.
