Add tests to test that through associations are not readonly, and we …

…can update the records we retrive from the association

activerecord/test/cases/associations/has_many_through_associations_test.rb

@@ -688,6 +688,17 @@ def test_include_method_in_association_through_should_return_true_for_instance_a
     assert author.comments.include?(comment)
   end
 
+  def test_through_association_readonly_should_be_false
+    assert !people(:michael).posts.first.readonly?
+    assert !people(:michael).posts.all.first.readonly?
+  end
+
+  def test_can_update_through_association
+    assert_nothing_raised do
+      people(:michael).posts.first.update_attributes!(:title => "Can write")
+    end
+  end
+
   def test_has_many_through_polymorphic_with_primary_key_option
     assert_equal [categories(:general)], authors(:david).essay_categories