Of course, testing is an important skill all developers need to have. We have a complete chapter to talk about testing and discuss TDD, unit testing, and end-to-end testing.

The test command comes with the --watch and the --env flags. Use the watch option to tell the CLI to detect changes in the test folder and execute the tests again.

In order to run tests, the CLI uses Karma, which is a test runner technology that is configured to use Jasmine testing framework to write all our testing files that should be saved into the test folder.

For example, the preceding command will run the app.sec.js file located in the test/unit folder:

au test --watch --env stage

The following is the output that has executed one test successfully: