Add a test to verify correct behavior when creating a polymorphic association

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3440 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/test/associations_join_model_test.rb

@@ -39,6 +39,14 @@ class AssociationsJoinModelTest < Test::Unit::TestCase
     assert_equal tags(:general), posts(:thinking).tags.first
   end
   
+  def test_polymorphic_has_many_create_model_with_inheritance
+    post = posts(:thinking)
+    assert_instance_of SpecialPost, post
+    
+    tagging = tags(:misc).taggings.create(:taggable => post)
+    assert_equal "Post", tagging.taggable_type
+  end
+  
   def test_has_many_with_piggyback
     assert_equal "2", categories(:sti_test).authors.first.post_id.to_s
   end

activerecord/test/fixtures/tag.rb

@@ -1,2 +1,3 @@
 class Tag < ActiveRecord::Base
+  has_many :taggings, :as => :taggable
 end