Thank you very much for creating this!
Before parting, let’s take a moment to see what we have accomplished. We’ve written an entire application without opening our browsers. When was the last time you did that?
Very nice 
The one piece of feedback I would like to share after reading through it (some sections thoroughly, some sections skimmingly) is that you do not mention property-based testing. Even if only as a footnote, mentioning it might help people to discover it as one more cool tool for their testing toolbox.
