diff --git a/actionpack/lib/action_controller/integration_test.rb b/actionpack/lib/action_controller/integration_test.rb
index 6cca3ff4a3..f99ef7ed7f 100644
--- a/actionpack/lib/action_controller/integration_test.rb
+++ b/actionpack/lib/action_controller/integration_test.rb
@@ -231,6 +231,11 @@ def process(method, path, parameters=nil, headers=nil)
           @request = @controller.request
           @response = @controller.response
 
+          # Decorate the response with the standard behavior of the TestResponse
+          # so that things like assert_response can be used in integration
+          # tests.
+          @response.extend(TestResponseBehavior)
+
           parse_result
           return status
         end
diff --git a/actionpack/lib/action_controller/test_process.rb b/actionpack/lib/action_controller/test_process.rb
index 405396ddae..07ef94aad2 100644
--- a/actionpack/lib/action_controller/test_process.rb
+++ b/actionpack/lib/action_controller/test_process.rb
@@ -121,7 +121,9 @@ def initialize_default_values
       end
   end
 
-  class TestResponse < AbstractResponse #:nodoc:
+  # A refactoring of TestResponse to allow the same behavior to be applied
+  # to the "real" CgiResponse class in integration tests.
+  module TestResponseBehavior #:nodoc:
     # the response code of the request
     def response_code
       headers['Status'][0,3].to_i rescue 0
@@ -251,6 +253,10 @@ def binary_content
     end
   end
 
+  class TestResponse < AbstractResponse #:nodoc:
+    include TestResponseBehavior
+  end
+
   class TestSession #:nodoc:
     def initialize(attributes = {})
       @attributes = attributes