@controller may not be defined here, and if so, it causes a Ruby warning

e.g. via test-unit-rails' `run_setup`

Author: amatsuda

actionview/lib/action_view/test_case.rb

@@ -284,7 +284,7 @@ def method_missing(selector, *args)
 
       def respond_to_missing?(name, include_private = false)
         begin
-          routes = @controller.respond_to?(:_routes) && @controller._routes
+          routes = defined?(@controller) && @controller.respond_to?(:_routes) && @controller._routes
         rescue
           # Don't call routes, if there is an error on _routes call
         end