I find that by building a test, I get to know what the code is doing and why better than any other way. It's a great learning experience. Also, while thinking

I find that by building a test, I get to know what the code is doing and why better than any other way. It's a great learning experience. Also, while thinking and building about a test, I think of simplifications and new features to add. Why? It's because technically, a test actually uses the code. If you and your code are friends, prepare to become lovers.