routes.rb

TestingInvitable::Application.routes.draw do
  root :to => "home#index"

  devise_for :users, :controllers => {:invitations => 'user_invitations'}
  devise_scope :user do
    get "sign_out", :to => "devise/sessions#destroy"
  end
end

user_invitations_controller.rb

require 'spec_helper'
describe UserInvitationsController do
  let(:user) { User.new }
  let(:job) { Job.new }  
  before :each do
    @request.env["devise.mapping"] = Devise.mappings[:user]
    @user = User.new(:email=>'sergio@enpijama.es', :password=>'11112222', :password_confirmation=>'11112222')
    sign_in @user
    UserInvitationsController.any_instance.should_receive(:current_user).at_least(1).and_return user
    @user_params = HashWithIndifferentAccess.new({ "email" => "joe@blow.com" })
    UserInvitationsController.any_instance.stub(:resource_params).and_return @user_params
    @user_email_mock = User.should_receive(:find_by_email).with(@user_params[:email])
    @user_params.should_receive(:[]=).with(:can_create,false)
    @job_params = HashWithIndifferentAccess.new({"organizable_type" => "Company", "organizable_id" => 99 })
     Job.should_receive(:new).and_return job # .with(@job_params)
  end
   it "should let you invite users to join your company" do
     post :create, {:user => @user_params, :job => @job_params}, :format => :json
   end
end