If you want to build robust applications with minimum defects, you should test your code. Even if you are very good at coding, sometimes you may forget a validation or break a dependency and won't know about it until the final user of your application finds the bug.
As a professional developer, you should make sure that your code is always ready for production; one way to successfully do it is to run tests in your development workflow. Another benefit of testing applications is that you will gain confidence in your code, which means that you can improve your code without the fear of breaking something accidentally.
In Backbone, testing depends on the responsibility of the object that you are testing. Models, views, controllers, and facades are tested in their own way. However, it doesn't matter what the object is, Jasmine does a great work in order to help you to make a good test battery.
In the next chapter, you will learn how to deploy your Backbone application to a server for production...