diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
index 1192b30b14..08ab4dc600 100644
--- a/activerecord/test/cases/serialized_attribute_test.rb
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -13,6 +13,10 @@ class SerializedAttributeTest < ActiveRecord::TestCase
 
   MyObject = Struct.new :attribute1, :attribute2
 
+  # NOTE: Use a duplicate of Topic so attribute
+  # changes don't bleed into other tests
+  Topic = ::Topic.dup
+
   teardown do
     Topic.serialize("content")
   end