Frontend Testing Documentation: vitest.dev | testing-library.com Framework & Location - Framework : Vitest + @testing-library/svelte - Location : Co-locate with code as or - TDD workflow : When fixing bugs or adding features, write a failing test first AAA Pattern Use explicit Arrange, Act, Assert regions: Testing with Spies Query Selection Priority Use accessible queries (not implementation details): 1. — Role-based (preferred) 2. — Label-based 3. — Text-based 4. — Test ID (fallback) 5. ❌ — Never use implementation details Mocking Modules ---