1 files changed, 8 insertions, 0 deletions
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index d033c1e760..b1a6f13111 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -81,11 +81,19 @@ class TestNestedAttributesInGeneral < ActiveRecord::TestCase
 end
 
 class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
+  include AssertRaiseWithMessage
+
   def setup
     @pirate = Pirate.create!(:catchphrase => "Don' botharrr talkin' like one, savvy?")
     @ship = @pirate.create_ship(:name => 'Nights Dirty Lightning')
   end
 
+  def test_should_raise_argument_error_if_trying_to_build_polymorphic_belongs_to
+    assert_raise_with_message ArgumentError, "Cannot build association looter. Are you trying to build a polymorphic one-to-one association?" do
+      Treasure.new(:name => 'pearl', :looter_attributes => {:catchphrase => "Arrr"})
+    end
+  end
+
   def test_should_define_an_attribute_writer_method_for_the_association
     assert_respond_to @pirate, :ship_attributes=
   end