Ultimate Kotlin testing skill. Use this whenever writing, reviewing, or debugging ANY Kotlin test — unit, integration, property-based, or coroutine. Covers TDD (RED/GREEN/REFACTOR), Kotest + MockK + Kover, anti-pattern detection, and four-pillar quality framework. Triggers on: write a test, add coverage, why is this test fragile, should I test this, how do I mock X, is this a good test, audit my tests, refactor this test, or any task involving Kotlin test files.
