Rspec mode provides some convenience functions related to dealing with RSpec.

I recommend installing via ELPA, but manual installation is simple as well:

(add-to-list 'load-path "/path/to/rspec-mode")
(require 'rspec-mode)

If rspec-mode is installed properly, it will be started automatically when ruby-mode is started.

See rspec-mode.el for further usage.

If you use ZSH and RVM, you may encounter problems running the specs. It may be so that an older version of Ruby, than the one you specified in .rvmrc, is used. This is because ZSH runs a small script each time a shell is created, which modifies the $PATH. The problem is that it prepends some default paths, such as /usr/bin, which contains another ruby binary.

What you can do to solve this is to use BASH for running the specs. This piece of code does the job:

(defadvice rspec-compile (around rspec-compile-around)
  "Use BASH shell for running the specs because of ZSH issues."
  (let ((shell-file-name "/bin/bash"))
    ad-do-it))
(ad-activate 'rspec-compile)