title: mongoid, rspec and assigns(:people) issue
body: <p>I'm trying to write my first specs for the People Controller
  Using mongoid (2.0.1), rspec (2.5.0), mongoid-rspec (1.4.2) and fabrication (0.9.5), if necessary.</p>
  
  <p>(remark: the Organization model mocked inherits from the Person model)</p>
  
  <pre><code>describe PeopleController do
    describe "as logged in user" do
      before (:each) do
        @user = Fabricate(:user)
        sign_in @user
      end
  
      describe "GET 'index'" do
        def mock_person(stubs={})
          @mock_person ||= mock_model(Person, stubs).as_null_object
  #        @mock_person ||= Fabricate.build(:organization)       
        end
  
        it "should be successful" do
          get :index
          response.should be_success
        end
  
        it "assigns all people as @people" do
          Person.stub(:all) { [mock_person] }
          get :index
          assigns(:people).should eq(mock_person)
        end
      end
    end
  </code></pre>
  
  <p>I get the <strong>following error message</strong> when I run this spec:</p>
  
  <pre><code>    1) PeopleController as logged in user GET 'index' assigns all people as @people
         Failure/Error: assigns(:people).should eq(mock_person)
  
           expected #&lt;Person:0x811b8448 @name="Person_1001"&gt;
                got #&lt;Mongoid::Criteria
             selector: {},
             options:  {},
             class:    Person,
             embedded: false&gt;
  
  
           (compared using ==)
  
           Diff:
           @@ -1,2 +1,6 @@
           -#&lt;Person:0x811b8448 @name="Person_1001"&gt;
           +#&lt;Mongoid::Criteria
           +  selector: {},
           +  options:  {},
           +  class:    Person,
           +  embedded: false&gt;
         # ./spec/controllers/people_controller_spec.rb:24:in `block (4 levels) in &lt;top (required)&gt;'
  </code></pre>
  
  <p>My controller is DRY thanks to inherited_resources (1.2.2) and works in development mode as it should.</p>
  
  <pre><code>class PeopleController &lt; InheritedResources::Base
    actions :index
  end
  </code></pre>
  
  <p>Any ideas what I'm doing wrong <code>Mongoid::Criteria</code> object?</p>
  
  <p>Thanks in advance</p>