One of the minor disappointments of Ruby on Rails: Up and Running was that like so many other texts didn’t get to the testing topics until the last chapter. There reasoning was:
We’ve come this far with our Photo Share web application, but we haven’t yet created any tests. In truth, this was deliberate. You had enough new things to learn as it was.
This isn’t because the authors think it was a “nice to have” topic since they declare that:
…automated testing is probably the single most important thing you can do to increase the quality and reliability of your software.
It’s just that everyone assumes that testing is still not a mainstream assumption, so it’s a bit of an advanced topic to be looked at after you’ve debugged your way through all the tutorial features.
I’ll be really glad when someone just starts the darn book with testing and without needing to put TDD in the title.