Jest

🃏 Delightful JavaScript Testing

• 👩🏻‍💻 Developer Ready: Complete and ready to set-up JavaScript testing solution. Works out of the box for any React project.

• 🏃🏽 Instant Feedback: Failed tests run first. Fast interactive mode can switch between running all tests or only test files related to changed files.

• 📸 Snapshot Testing: Jest can capture snapshots of React trees or other serializable values to simplify UI testing.

Read More: http://facebook.github.io/jest/