ruby-on-rails-4 - 未定义的方法 'document' 为 nil :NilClass while running Rails-tutorial with rspec

Question

我正在关注 railstutorial by Michael Hartl ，我不明白 中测试失败的原因第5章 .这本书使用了 minitest 框架，但我决定使用 RSpec。为此，我删除了 test 文件夹并包含了 rspec-rails在我的 Gemfile 中，然后运行 ​​bundle install 和 rails g rspec:install生成我的规范文件夹。但是，有一些我觉得用 minitest 语法运行起来很方便的测试，例如 assert_select在 static_pages_controller_spec.rb 文件中。这是我的规范文件的样子:

require "rails_helper"

RSpec.describe StaticPagesController, type: :controller do
  describe "GET #home" do
    it "returns http success" do
      get :home
      expect(response).to have_http_status(:success)
    end
    it "should have the right title" do
      get :home
      assert_select "title", "Ruby on Rails Tutorial Sample App"
    end
  end

  describe "GET #help" do
    it "returns http success" do
      get :help
      expect(response).to have_http_status(:success)
    end
    it "should have the right title" do
      get :help
      assert_select "title", "Help | Ruby on Rails Tutorial Sample App"
    end
  end

  describe "GET #about" do
    it "returns http success" do
      get :about
      expect(response).to have_http_status(:success)
    end
    it "should have the right title" do
      get "about"
      assert_select "title", "About | Ruby on Rails Tutorial Sample App"
    end
  end
end

当我使用 RSpec 运行测试时，这是我得到的失败错误:

StaticPagesController GET #home should have the right title
 Failure/Error: assert_select "title", "Ruby on Rails Tutorial Sample App"

 NoMethodError:
   undefined method `document' for nil:NilClass
# ./spec/controllers/static_pages_controller_spec.rb:11:in `block (3 levels)
in <top (required)>'

同样的错误信息 (No Method error)出现在每个失败的测试中。

我该如何解决？是不是我做错了什么。

Answer 1

此错误的原因是默认情况下 RSpec 不呈现 Controller 规范的 View 。您可以为特定的一组规范启用 View 渲染，如下所示:

describe FooController, type: :controller do
  render_views

  # write your specs
end

或者您可以通过在 RSpec 配置中的某处添加它来全局启用它:

RSpec.configure do |config|
  config.render_views
end

见 https://www.relishapp.com/rspec/rspec-rails/v/2-6/docs/controller-specs/render-views想要查询更多的信息。