Make sure the flash method is defined even if helpers are not present

actionpack/lib/action_controller/metal/flash.rb

@@ -33,12 +33,10 @@ def add_flash_types(*types)
         types.each do |type|
           next if _flash_types.include?(type)
 
-          if respond_to? :helper_method
           define_method(type) do
             request.flash[type]
           end
-            helper_method type
-          end
+          helper_method(type) if respond_to?(:helper_method)
 
           self._flash_types += [type]
         end

actionpack/test/controller/flash_test.rb

@@ -343,11 +343,18 @@ def test_flash_factored_into_etag
   end
 
   def test_flash_usable_in_metal_without_helper
+    controller_class = nil
+
     assert_nothing_raised do
-      Class.new ActionController::Metal do
+      controller_class = Class.new(ActionController::Metal) do
         include ActionController::Flash
       end
     end
+
+    controller = controller_class.new
+
+    assert_respond_to controller, :alert
+    assert_respond_to controller, :notice
   end
 
   private