polymorphic_spec.rb

    # ....
    describe "#build" do

      context "when the parent is new" do
        let(:movie) { Movie.new }
        let!(:rating) { movie.ratings.build }

        it "appends the document to the association" do
          movie.ratings.first.should == rating
        end

        it "sets the reverse association's ids" do
          rating.ratable.should == movie
          rating.ratable_id.should == movie.id
          rating.ratable_type.should == movie.class.name
        end
      end

      context "when the parent is not new" do
        let(:avatar) do
          Movie.new.tap do |movie|
            movie.instance_variable_set(:@new_record, false)
          end
        end
        let!(:rating) { avatar.ratings.build }

        it "appends the document to the association" do
          avatar.ratings.first.should == rating
        end

        it "sets the reverse association's ids" do
          rating.ratable.should == avatar
          rating.ratable_id.should == avatar.id
          rating.ratable_type.should == avatar.class.name
        end
      end

    end
    # ....
__END__


1) Mongoid::Associations::Options polymorphic association #build when the parent is new sets the reverse association's ids
    Failure/Error: rating.ratable.should == movie
    Document not found for class Movie with id(s) 4c49c094f7e2da4ad7000020
    # ./spec/../lib/mongoid/contexts/ids.rb:19:in `id_criteria'
    # ./spec/../lib/mongoid/criteria.rb:31:in `__send__'
    # ./spec/../lib/mongoid/criteria.rb:31:in `id_criteria'
    # ./spec/../lib/mongoid/criteria.rb:195:in `translate'
    # ./spec/../lib/mongoid/finders.rb:67:in `find'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:17:in `initialize'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:36:in `new'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:36:in `instantiate'
    # ./spec/../lib/mongoid/associations.rb:261:in `ratable'
    # ./spec/../lib/mongoid/memoization.rb:11:in `memoized'
    # ./spec/../lib/mongoid/associations.rb:261:in `ratable'
    # ./spec/unit/mongoid/associations/polymorphic_spec.rb:22

2) Mongoid::Associations::Options polymorphic association #build when the parent is not new appends the document to the association
    Failure/Error: avatar.ratings.first.should == rating
    expected: #<Rating _id: 4c49c094f7e2da4ad7000026, ratable_type: "Movie", ratable_id: "4c49c094f7e2da4ad7000025", score: nil>,
         got: nil (using ==)
    # ./spec/unit/mongoid/associations/polymorphic_spec.rb:37

3) Mongoid::Associations::Options polymorphic association #build when the parent is not new sets the reverse association's ids
    Failure/Error: rating.ratable.should == avatar
    Document not found for class Movie with id(s) 4c49c094f7e2da4ad700002a
    # ./spec/../lib/mongoid/contexts/ids.rb:19:in `id_criteria'
    # ./spec/../lib/mongoid/criteria.rb:31:in `__send__'
    # ./spec/../lib/mongoid/criteria.rb:31:in `id_criteria'
    # ./spec/../lib/mongoid/criteria.rb:195:in `translate'
    # ./spec/../lib/mongoid/finders.rb:67:in `find'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:17:in `initialize'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:36:in `new'
    # ./spec/../lib/mongoid/associations/referenced_in.rb:36:in `instantiate'
    # ./spec/../lib/mongoid/associations.rb:261:in `ratable'
    # ./spec/../lib/mongoid/memoization.rb:11:in `memoized'
    # ./spec/../lib/mongoid/associations.rb:261:in `ratable'
    # ./spec/unit/mongoid/associations/polymorphic_spec.rb:41