In this chapter, you learned the importance of testing your code using unit tests. You now know how to configure PHPUnit on your application so that you can not only run your tests but also get good feedback. You got a good introduction on how to write unit tests properly, and now, it is safer for you to introduce changes in your application.
In the next chapter, we will study some existing frameworks, which you can use instead of writing your own every time you start an application. In this way, not only will you save time and effort, but also other developers will be able to join you and understand your code easily.