CHT Technology Radar for ContributorsCHT Technology Radar for Contributors

Jest

quality
This item was not updated in last three versions of the Radar. Nevertheless, it remains pertinent.
Assess

Jest is an open-source JS-based testing framework maintained by Facebook. It is designed to be easy to use and provides a comprehensive set of tools for writing end-to-end, integration, and unit tests for JavaScript applications. It is a complete and ready to set up JavaScript testing solution.

In the CHT, Jest is used to test cht-interoperability.

Advantages

  • Easy to use: Jest is intuitive and easy to set up, making it ideal for beginners and experienced developers.
  • Extensive test coverage: Jest provides a complete set of tools for writing unit, integration, and end-to-end tests.
  • Integration with other frameworks: Jest integrates well with projects that use React, but can also be used with other JavaScript frameworks (​​Babel, TypeScript, Node, React, Angular, Vue and more).
  • Fast and efficient: Jest uses parallel test execution and other techniques to speed up test execution time.
  • Provides testing support for asynchronous code.
  • It is maintained and well-documented, making it easy to learn.
  • Code Coverage: Jest provides built-in code coverage reports to help developers identify areas not covered by tests.

Drawbacks

  • Compared to Jasmine and other frameworks, not many libraries and toolings are supported by Jest.
  • People not comfortable with the Jest framework have asserted that the learning curve is pretty hard.
  • Leveraging auto-mocking can make tests slow. This is because the more dependencies a module has, the more work needs to be done by Jest to mock it, which comes at the cost of performance.
  • Snapshot testing with Jest is not so feasible for larger snapshot files containing thousands of lines.
  • Its debugging capabilities need improvement.

Market - Current Adoption

Jest has over 10 million dependent repos on GitHub. Prominent companies that reportedly adopt Jest in their tech stack are: Facebook, Airbnb, Spotify, The New York Times, Travel Perk, Twitter, Instagram, etc. Stateofjs collects data from thousands of front-end developers in its annual surveys. Here’s their most recent ranking of most popular JS testing frameworks, sorted by their usage and Jest is at the top 3.