Testing software. There are a ton of reasons we do it. Here are a two of mine:

Speeds up my workflow so I can develop software faster Helps me ensure I don't break existing code when making changes

That said, I have a few questions for you (these are twitter polls):

The goal of this newsletter is to get each of you to be able to answer "Yes" to that last question. So you have a fundamental understanding of what a test in JavaScript even is which will help you write better tests.