JHipster uses a combination of Karma, Mocha, Chai, and Enzyme to unit test the client-side components.
Karma (https://karma-runner.github.io/2.0/index.html) is used as the test runner and Mocha (https://mochajs.org/) is used as the testing framework. Chai (http://chaijs.com/) is an assertion library with great plugin support. We use its BDD (Behavior-driven development) style assertions. Enzyme (http://airbnb.io/enzyme/) is a testing utility for React which makes it easy to unit test React components. In combination, these libraries provide a rich and intuitive testing environment for React.
Let's run the generated unit tests. Run yarn test in a Terminal.