Vitest Fast unit testing powered by Vite. Write tests that run in Node or browser environments. Setup & Config Running Tests Writing Tests Use Given-When-Then structure with nested blocks for clarity: Test Quality Guidelines - Independent : no shared state between tests - Deterministic : same result every run - Focused : one assertion focus per test - Fast : unit tests under 100ms - Clear : minimal setup, obvious assertions Test business logic, edge cases, error handling, and public API contracts. Skip trivial getters/setters, third-party libraries, and UI layout. Mocking - Module mocking: fo…