Testing React Components with Jest and RTL

React Testing Library (RTL) encourages tests that resemble how users interact with your UI-queries by role, label, and text instead of implementation details.

A Simple Component Test

import { render, screen, fireEvent } from '@testing-library/react';
import Counter from './Counter';

test('increments count on click', () => {
  render(<Counter />);
  fireEvent.click(screen.getByRole('button', { name: /increment/i }));
  expect(screen.getByText(/count: 1/i)).toBeInTheDocument();
});

What to Test

Focus on user-visible behavior: forms submit, errors display, loading states appear. Mock network with MSW (Mock Service Worker) instead of mocking fetch in every test.

Integration vs Unit

RTL tests are integration-leaning by nature. Reserve shallow unit tests for pure utilities and hooks tested with @testing-library/react-hooks.

Conclusion

Tests give confidence when refactoring hooks and context. Invest in a fast CI feedback loop-slow test suites get skipped, and that defeats the purpose.