In this chapter, we explored the world of testing, exceptions, and profiling.

I tried to give you a fairly comprehensive overview of testing, especially unit testing, which is the kind of testing that a developer mostly does. I hope I have succeeded in channeling the message that testing is not something that is perfectly defined that you can learn from a book. You need to experiment with it a lot before you get comfortable. Of all the efforts a coder must make in terms of study and experimentation, I'd say testing is the one that is the most important.

We briefly saw how we can prevent our program from dying because of errors, called exceptions, that happen at runtime. And, to steer away from the usual ground, I have given you an example of a somewhat unconventional use of exceptions to break out of nested for loops. That's not the only case, and I'm sure you'll discover others as you grow as a coder.

At the end, we very briefly touched on profiling, with a simple example and a few guidelines. I wanted to talk about profiling for the sake of completeness, so at least you can play around with it.

In the next chapter, we're going to explore the wonderful world of secrets, hashing, and creating tokens.