Rails Test Prescriptions is a comprehensive guide to testing Rails applications, covering Test-Driven Development from both a theoretical perspective (why to test) and from a practical perspective (how to test effectively). It covers the core Rails testing tools and procedures for Rails 2 and Rails 3, and introduces popular add-ons, including Cucumber, Shoulda, Machinist, Mocha, and Rcov.
I was completely overwhelmed by the shear volume of rails testing tools, and this book provided a good overview of many different tools and provided a kind of map of the landscape. Additionally, the book was not as dogmatic as one would expect a book on rails testing to be. That said, the quality of writing was not great, the book seemed to contain many errors. The most grievous sin is that at the end of it I don't know that I came away with any insights that would make me a better tester, the book was too shallow for me to learn anything deep.
It was good enough the first the time I read it. It is best to explore test frameworks especially the default ones like minitest. Overall, I think this book is still enough for those who to know more tools.