Mocking a non database backed model in Rails with Rspec

I am trying to create a non ActiveRecord model in my Ruby on Rails application according to http://railscasts.com/episodes/121-non-active-record-model. I am facing hard time testing it though.

I have following class in my app/models/sms.rb file.

class Sms
  def initialize
    # Do stuff here
  end

  def deliver
    # Do some stuff here
  end
end

I am unable to mock deliver method on my Sms class.

it 'should do someting' do
  @sms = mock(Sms)
  @sms.should_receive(:deliver).and_return(true)

  post :create, :user_id => @user.id
  flash[:notice].should == "SMS sent successfully."
  response.should redirect_to(some_url)
end

In my controller code I do have a line that says @sms.deliver. Yet above gives following error:

   Failure/Error: @sms.should_receive(:deliver).and_r开发者_StackOverflow中文版eturn(true)
      (Mock Sms).deliver(any args)
      expected: 1 time
      received: 0 times

Any pointers?

Variables beginning with @ are instance variables. The @sms your controller refers to is not the same @sms as your spec has defined.

Try changing

@sms = mock(Sms)
@sms.should_receive(:deliver).and_return(true)

to

Sms.any_instance.should_receive(:deliver).and_return(true)

If your version of RSpec doesn't have the any_instance method, you'll need to stub :new on the class:

@sms = mock(Sms)
Sms.stub(:new).and_return(@sms)
@sms.should_receive(:deliver).and_return(true)