How do you test React components?

Testing React applications involves different tools for different levels of confidence.

React Testing Library (RTL) is the standard for component testing. It encourages testing components the way users interact with them—finding elements by accessible roles, labels, or text rather than implementation details. render() your component, query for elements, simulate user events, and assert on results.

Jest provides the test runner and assertion library. It handles mocking, code coverage, and test organization. Combined with RTL, it's the foundation for most React testing setups.

For unit testing hooks or utilities, Jest alone works great. Extract complex logic into custom hooks or pure functions, then test them in isolation without rendering components.

End-to-end testing with Playwright or Cypress tests your entire application as a user would experience it. These tests are slower but catch integration issues that unit tests miss. Use them for critical user flows: signup, checkout, core features.

A healthy testing strategy balances these levels. Many component tests (fast, focused), some integration tests (key flows), and few E2E tests (critical paths). Test behavior, not implementation—this makes tests more resilient to refactoring.