There is some problem with rspec V3. But in your case you are using V2.
change
require 'rails_helper'
to
require 'spec_helper'
Other description find here https://teamtreehouse.com/forum/problem-with-rspec
For V3 :
If someone using rspec V3 then similar error occurs when generator not run. So before trying anything run generator.
rails generate rspec:install
If you are getting a huge list of warning on your console. Then you need to remove --warnings from .rspec file.