What problem does it solve? Writing tests for Flix game projects often leads to brittle, low-value tests: hardcoded numbers that break on balance tuning, multiple assertions per test, duplicated mocks, and tests that merely restate the code. This Skill provides a complete test design policy so every @Test is meaningful, maintainable, and consistent. ## Core Features & Use Cases - Test Scope Rules: Defines exactly what to test (game rules, progression, JSON/Doc bridging) and what not to test (motion, coordinates, trivial getters). - Doc-Derived Expectations: Requires expected values to be derived from Doc (JSON defaults) instead of pasted numeric literals, so balance changes never break tests. - Structural Conventions: Enforces one assertion per test (tuple packing), bug! for unreachable match branches, effect-polymorphic mock helpers, and round-number test data. - Use Case: When you create a new Scene module or edit Game.flix logic, apply this Skill to write a test file that verifies state transitions and boundary conditions with clean, readable assertions. ## Quick Start Ask the AI to write tests for a new Flix module following the quality-assurance test design guidelines.
