testing-guidelines

To write deterministic Vitest tests, use scoped mocks, isolate test execution, and apply fake timers to control time-dependent behavior. This ensures your tests pass consistently regardless of execution order and eliminates flaky test runs.

Using Testing Library queries like getByRole and getByText validates real user-facing behavior instead of brittle implementation details. This approach focuses assertions on accessible elements and visible text, making your component tests resilient to internal refactoring.

The best way to structure React tests is by colocating *.test.ts(x) files directly alongside your source code. This convention covers unit tests for utility functions and component tests for UI elements, keeping relevant tests easy to locate and maintain.

Yes, you can use Playwright for visual regression verification alongside Vitest and jsdom. Vitest handles unit and component testing logic, while Playwright executes browser-based visual regression checks during development to validate UI appearance.

You should skip or fail tests during development by following clear execution rules defined by your testing conventions. Applying these structured rules for skipping or failing ensures that incomplete features do not disrupt the deterministic execution of the overall test suite.