tests for namespaced controlleler

lib/active_model/array_serializer.rb

@@ -39,7 +39,7 @@ module ActiveModel
 
     def serializable_object
       @object.map do |item|
-        serializer_for(item).serializable_object
+        serializer_for(item).serializable_object_with_notification
       end
     end
     alias_method :serializable_array, :serializable_object

lib/active_model/serializable.rb

@@ -12,6 +12,12 @@ module ActiveModel
       end
     end
 
+    def serializable_object_with_notification
+      instrument('!serialize') do
+        serializable_object
+      end
+    end
+
     def serializable_data
       embedded_in_root_associations.tap do |hash|
         if respond_to?(:meta) && meta