Jest is a JavaScript testing framework developed by Facebook with zero-configuration, built-in assertion library, snapshot testing, mocking system, and coverage reporting. Jest supports parallel test execution to significantly improve test speed. It also provides powerful CLI tools and rich APIs, making test writing simple and intuitive. Jest is suitable for testing React components, Node.js applications, and various JavaScript projects.
Core Features:
- Zero Configuration: Ready to use out of the box
- Built-in Assertions: Rich assertion methods
- Snapshot Testing: Easily capture component output
- Mocking System: Powerful mock and spy functionality
- Parallel Execution: Automatically run tests in parallel
- Coverage Reports: Built-in code coverage statistics
Use Cases: Jest is widely used in frontend testing, especially for unit tests, integration tests, and end-to-end tests in React projects. It's also suitable for testing Node.js backend services.