Writing unit tests is not about using the latest and greatest unit testing tools and libraries. It is simply about testing little pieces of the code in isolation. The simple fact which we should always keep in mind is that the main goal of unit testing is to ensure the proper functionality and integrity of our code. Even if you are not familiar with any unit testing tools, you can still write you own unit tests, using the skills that you already have in JavaScript.
However, as you will see later in this chapter, using third-party tools and frameworks can greatly help us to write better and more sophisticated tests.
For the rest of the chapter, we will target two of our sub-modules (CookieHandler and StorageHandler) and will write some simple unit tests for them. We will also explore how our modular architecture can help us write targeted and independent unit tests for each module.