ruby-on-rails - Rails 3.2 引擎测试中的模板错误

Question

我创建了简单的引擎。一切正常，但是当我尝试为引擎控制器编写功能测试时，出现如下错误：

3) Error:
test_should_get_new(Supportilla::SessionsControllerTest):
ActionView::Template::Error: No route matches {}

我的测试文件 test/functional/supportilla/sessions_controller_test.rb：

require 'test_helper'

module Supportilla
  class SessionsControllerTest < ActionController::TestCase   
    test "should get new" do
      get "new", use_route: "supportilla"
      assert_response :success
    end

    test "should get create" do
      post :create, { session: { username: "test", password: "123"},
        use_route: :supportilla }
      assert_response :success
    end
    ...
  end
end

并且引擎安装在 test/dummy/config/routes.rb 中：

mount Supportilla::Engine => "/supportilla"

耙路线：

Routes for Supportilla::Engine:
    signin GET    /signin(.:format)             supportilla/sessions#new
   signout GET    /signout(.:format)            supportilla/sessions#destroy
           POST   /signin(.:format)             supportilla/sessions#create
       ...

我很困惑，希望得到你的帮助。