setup_request

# File actionpack/lib/action_controller/test_case.rb, line 577
        def setup_request(controller_class_name, action, parameters, session, flash, xhr)
          generated_extras = @routes.generate_extras(parameters.merge(controller: controller_class_name, action: action))
          generated_path = generated_path(generated_extras)
          query_string_keys = query_parameter_names(generated_extras)

          @request.assign_parameters(@routes, controller_class_name, action, parameters, generated_path, query_string_keys)

          @request.session.update(session) if session
          @request.flash.update(flash || {})

          if xhr
            @request.set_header "HTTP_X_REQUESTED_WITH", "XMLHttpRequest"
            @request.fetch_header("HTTP_ACCEPT") do |k|
              @request.set_header k, [Mime[:js], Mime[:html], Mime[:xml], "text/xml", "*/*"].join(", ")
            end
          end

          @request.fetch_header("SCRIPT_NAME") do |k|
            @request.set_header k, @controller.config.relative_url_root
          end
        end