The Testing Pyramid
The testing pyramid suggests you should have many unit tests, fewer integration tests, and even fewer end-to-end tests. This balance provides good coverage while keeping test suites fast and maintainable.
Unit Testing
Unit tests verify individual functions or components in isolation. They're fast, easy to write, and provide immediate feedback. Use Jest or Vitest for JavaScript projects.
describe('calculateTotal', () => {
it('should sum all item prices', () => {
const items = [{ price: 10 }, { price: 20 }];
expect(calculateTotal(items)).toBe(30);
});
});Integration Testing
Integration tests verify that different parts of your system work together correctly. Test API endpoints, database interactions, and third-party integrations.
E2E Testing
End-to-end tests simulate real user scenarios. Use tools like Playwright or Cypress to test complete user flows through your application.