    # File lib/action_controller/test_process.rb, line 409
        def build_request_uri(action, parameters)
          unless @request.env['REQUEST_URI']
            options = @controller.send(:rewrite_options, parameters)
            options.update(:only_path => true, :action => action)

            url = ActionController::UrlRewriter.new(@request, parameters)
            @request.set_REQUEST_URI(url.rewrite(options))
          end
        end