diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index <HASH>..<HASH> 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -479,7 +479,6 @@ module ActionController
         @request.session["flash"].sweep
 
         @controller.request = @request
-        @controller.params.merge!(parameters)
         build_request_uri(action, parameters)
         @controller.class.class_eval { include Testing }
         @controller.recycle!
We dont need to merge in the parameters as thats all being reset by the rack headers (and its causing problems for Strong Parameters attempt of wrapping request.parameters because it will change in testing)