NameError

I am getting the following rails error when I do my test on friendships:

1) Error: test_that_creating_a_friendship_works_without_raising_an_exception(UserFriendshipTest): NameError: uninitialized constant Mocha::Integration /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/mocha-0.10.5/lib/mocha/integration/mini_test/version_230_to_262.rb:36:in rescue in run' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/mocha-0.10.5/lib/mocha/integration/mini_test/version_230_to_262.rb:47:inrun' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit/testcase.rb:17:in run' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/testing/setup_and_teardown.rb:36:inblock in run' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/callbacks.rb:425:in _run__2226949997155820290__setup__3145843997473138674__callbacks' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/callbacks.rb:405:in__run_callback' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/callbacks.rb:385:in _run_setup_callbacks' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/callbacks.rb:81:inrun_callbacks' /Users/chrisdziewa/.rvm/gems/ruby-2.0.0-p353/gems/activesupport-3.2.13/lib/active_support/testing/setup_and_teardown.rb:35:in run' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:919:inblock in _run_suite' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:912:in map' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:912:in_run_suite' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:657:in block in _run_suites' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:655:ineach' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:655:in _run_suites' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:867:in_run_anything' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:1060:in run_tests' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:1047:inblock in _run' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:1046:in each' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:1046:in_run' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/minitest/unit.rb:1035:in run' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:21:inrun' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:774:in run' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:366:inblock (2 levels) in autorun' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:27:in run_once' /Users/chrisdziewa/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/test/unit.rb:365:inblock in autorun'

Finished tests in 0.115463s, 25.9823 tests/s, 25.9823 assertions/s. 3 tests, 3 assertions, 0 failures, 1 errors, 0 skips

#My gemfile

source 'https://rubygems.org'

gem 'rails', '3.2.13'

# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'


gem 'devise'
gem 'simple_form'
group :test do 
    gem 'shoulda'
end

group :development, :test do 
    gem 'sqlite3'
end

group :production do 
    gem 'pg'
end

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  # gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

#This is my user_friendship_test.rb file

require 'test_helper'

class UserFriendshipTest < ActiveSupport::TestCase
    should belong_to(:user)

    should belong_to(:friend)

    test "that creating a friendship works without raising an exception" do 
        assert_nothing_raised do
            UserFriendship.create users(:chris), friend: users(:mike)
        end
    end
end

#Here is my user_friendship.rb file

class UserFriendship < ActiveRecord::Base

  belongs_to :user
  belongs_to :friend

  attr_accessible :user, :friend
end

Any help would be greatly appreciated! Thanks guys!