Idea for new theme

Hello, I love your website and I am planning to purchase your books, I also recommend your website at work to others, because it is an awesome place for learning. I have an idea for you. You could make a new topic about testing code. I think it will nicely complement others topics. Because without tests refactoring is harder and without patterns, the testing is harder.

Have a nice day

P.S.: Sorry for my bad English