diff --git a/activemodel/test/cases/serializers/json_serialization_test.rb b/activemodel/test/cases/serializers/json_serialization_test.rb
index 734656b7492..e2eb91eeb0b 100644
--- a/activemodel/test/cases/serializers/json_serialization_test.rb
+++ b/activemodel/test/cases/serializers/json_serialization_test.rb
@@ -2,23 +2,6 @@ require 'cases/helper'
 require 'models/contact'
 require 'active_support/core_ext/object/instance_variables'
 
-class Contact
-  include ActiveModel::Serializers::JSON
-  include ActiveModel::Validations
-
-  def attributes=(hash)
-    hash.each do |k, v|
-      instance_variable_set("@#{k}", v)
-    end
-  end
-
-  remove_method :attributes if method_defined?(:attributes)
-
-  def attributes
-    instance_values
-  end
-end
-
 class JsonSerializationTest < ActiveModel::TestCase
   def setup
     @contact = Contact.new
diff --git a/activemodel/test/cases/serializers/xml_serialization_test.rb b/activemodel/test/cases/serializers/xml_serialization_test.rb
index 5db14c81571..22fca5bd171 100644
--- a/activemodel/test/cases/serializers/xml_serialization_test.rb
+++ b/activemodel/test/cases/serializers/xml_serialization_test.rb
@@ -3,18 +3,6 @@ require 'models/contact'
 require 'active_support/core_ext/object/instance_variables'
 require 'ostruct'
 
-class Contact
-  include ActiveModel::Serializers::Xml
-
-  attr_accessor :address, :friends, :contact
-
-  remove_method :attributes if method_defined?(:attributes)
-
-  def attributes
-    instance_values.except("address", "friends", "contact")
-  end
-end
-
 module Admin
   class Contact < ::Contact
   end
diff --git a/activemodel/test/models/contact.rb b/activemodel/test/models/contact.rb
index c25be28e1d9..bcfd267a344 100644
--- a/activemodel/test/models/contact.rb
+++ b/activemodel/test/models/contact.rb
@@ -1,8 +1,13 @@
 class Contact
   extend ActiveModel::Naming
   include ActiveModel::Conversion
+  include ActiveModel::Validations
+
+  include ActiveModel::Serializers::JSON
+  include ActiveModel::Serializers::Xml
 
   attr_accessor :id, :name, :age, :created_at, :awesome, :preferences
+  attr_accessor :address, :friends, :contact
 
   def social
     %w(twitter github)
@@ -23,4 +28,14 @@ class Contact
   def persisted?
     id
   end
+
+  def attributes=(hash)
+    hash.each do |k, v|
+      instance_variable_set("@#{k}", v)
+    end
+  end
+
+  def attributes
+    instance_values.except("address", "friends", "contact")
+  end
 end