Delightful JavaScript Testing

 Some features of this testing framework are:
  * Easy Setup: Jest is a complete and easy to set up JavaScript testing
  solution. In fact, Jest 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.
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 Node.js is an event-based server-side JavaScript engine.