react-testing-library

Install: npm install --save-dev @testing-library/react @testing-library/dom . Recommended extras: @testing-library/user-event and @testing-library/jest-dom . React 19 requires v16.1.0+. "The more your tests resemble the way your software is used, the more confidence they can give you." Avoid testing : Test instead : Use queries in this order of preference: When to use : Always use @testing-library/user-event over fireEvent : - Internal state of components - Internal methods - Lifecycle methods - Child component implementation details - What users see and interact with - Behavior from user's perspective - Accessibility (queries by role, label) - getBy* — element exists - queryBy* — element may not exist (assertions like expect(...).not.toBeInTheDocument() ) - findBy* — element appears asynchronously - Documentation - Releases - GitHub - npm