Reddit mentions of Rails Test Prescriptions (Pragmatic Programmers)

Honestly, not really. I've got copies of both The Cucumber Book and The Rspec Book and both are alright, but both are more than likely pretty much out of date. If you're looking for syntax, I'd just suggest reading the documentation for the relevant libraries.

I've heard okay/good things about Rails Test Prescriptions but haven't personally read it.

I have a few blog posts that I enjoy:

• http://mrjoy.com/2013/09/19/an-unusual-case-for-cucumber/
  
• http://collectiveidea.com/blog/archives/2010/09/13/practical-cucumber-organization/
  
• http://collectiveidea.com/blog/archives/2010/09/08/practical-cucumber-scenario-specific-steps/
  
• http://robots.thoughtbot.com/how-we-test-rails-applications (but I don't write Controller/View specs, instead testing those via feature tests)
  
  I've personally learned a non-trivial amount of testing methodology/principles in Ruby from Avdi Grimm, particularly:
  
  
• the multi-part stretches of RubyTapas (e.g. Gem-Love, PulseFFI)
  
• The Making of Cowsays
  
• Objects on Rails