1 files changed, 5 insertions, 3 deletions
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index f1ff57f0cb..70a5de7f30 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -462,9 +462,11 @@ module ActionController
     # The exception is stored in the exception accessor for further inspection.
     module RaiseActionExceptions
       def self.included(base)
-        base.class_eval do
-          attr_accessor :exception
-          protected :exception, :exception=
+        unless base.method_defined?(:exception) && base.method_defined?(:exception=)
+          base.class_eval do
+            attr_accessor :exception
+            protected :exception, :exception=
+          end
         end
       end