rubocop is a code style checker for Ruby. A similar tool to rubocop, Cane, can be integrated with Rake. I prefer rubocop to Cane since rubocop makes checks based on the Ruby Sty
You will probably find https://github.com/yujinakayama/guard-rubocop useful if you use Guard for your RSpec tests. It enables Rubocop to give you instant feedback as soon as you save the file, along with your test results.