respond_to_missing?

# File actionview/lib/action_view/test_case.rb, line 436
      def respond_to_missing?(name, include_private = false)
        begin
          routes = defined?(@controller) && @controller.respond_to?(:_routes) && @controller._routes
        rescue
          # Don't call routes, if there is an error on _routes call
        end

        routes &&
          (routes.named_routes.route_defined?(name) ||
           routes.mounted_helpers.method_defined?(name))
      end