Unit testing intro

Along with documentation, unit testing often gets left behind as a chore that should get done, but simply does not earn the attention from developers that it deserves. Maintaining and regularly running unit tests can have any number of beneficial effects on an application's development. These can include keeping the trunk stable, rather than having thoroughly untested changes create a ripple of frustration and lack of productivity hit other developers working on the same project.

More recently, unit testing has had a boost in popularity due to the Agile methods of software development, the short turnarounds of which thrive when the software has rigorous, frequent testing. No matter which methodology the development of an application follows, unit testing by individual developers can only help the quality and stability of the overall application.

For JavaScript, developers mostly use JsUnit, a JavaScript port of the Java JUnit unit testing tool. It works in all major browsers (IE6, IE7, Mozilla, Opera, and Safari), and provides a simple enough API to create tests almost immediately, while flexible enough to create entire nested suites of unit tests.