Add failing tests, according to #480.

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -66,6 +66,20 @@ def test_create_from_association_should_respect_default_scope
     assert_equal 'exotic', bulb.name
   end
 
+  def test_create_from_association_with_nil_values_should_work
+    car = Car.create(:name => 'honda')
+
+    bulb = car.bulbs.new(nil)
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.build(nil)
+    assert_equal 'defaulty', bulb.name
+
+    bulb = car.bulbs.create(nil)
+    assert_equal 'defaulty', bulb.name
+  end
+
+
   # When creating objects on the association, we must not do it within a scope (even though it
   # would be convenient), because this would cause that scope to be applied to any callbacks etc.
   def test_build_and_create_should_not_happen_within_scope