users_controller_spec.rb

require 'spec_helper'

describe UsersController do
  let(:user) { User.new }
  
  describe '#show' do
    it 'assigns @user' do
      user.stub(:find_by_username).and_return(User.new)

      get :show, :username => 'chridal' 

      assigns(:user).should be_a(User) 
    end
  end 

end