Testing React Applications
Harry
· 22 Sep 2026
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Unit Tests
Vitest plus Testing Library: render, query by role, fire events, assert visible behavior.
Mocking APIs
Spy on fetch or use MSW; cover loading, success and error states.
E2E Tests
Playwright or Cypress for login and critical flows; run the happy path in CI.
Key Points
- Test behavior, not implementation.
- Mock the network, not the component.
- Unit, integration, then one E2E per flow.