如何从截屏视频 #228 中为 Ryan Bates 的助手编写 RSpec 测试? [英] How to write an RSpec test for Ryan Bates' helper from screencast #228?

问题描述

我跟着Ryan Bates关于可排序表列的教程.

我尝试为 ApplicationHelper 编写规范，但 #link_to 方法失败.

I attempted to write a spec for the ApplicationHelper, but the #link_to method fails.

这是我的规格:

require "spec_helper"

describe ApplicationHelper, type: :helper do
  it "generates sortable links" do
    helper.sortable("books") #just testing out, w/o any assertions... this fails
  end
end

这是运行规范的输出:

1) ApplicationHelper generates sortable links
 Failure/Error: helper.sortable("books") #just testing out, w/o any assertions... this fails
 ActionController::UrlGenerationError:
   No route matches {:sort=>"books", :direction=>"asc"}
 # ./app/helpers/application_helper.rb:5:in `sortable'

app/helpers/application_helper.rb(可排序方法)

app/helpers/application_helper.rb(sortable method)

module ApplicationHelper
  def sortable(column, title = nil)
    title ||= column.titleize
    direction = (column == params[:sort] && params[:direction] == "asc") ? "desc" : "asc"
    link_to title, :sort => column, :direction => direction
  end
end

推荐答案

发生错误是因为在您的测试中，Rails 不知道 url 的控制器/操作是什么，以您生成 url 的方式，它会将 {:sort => column, :direction => direction} 附加到当前请求参数，但是因为没有参数，它会失败，所以一个简单的修复方法是:

the error is happening because in your test, Rails doesn't know what's the controller/action for the url, in the way that you are generating the url, it will append {:sort => column, :direction => direction} to the current request params, but because there are not params, it will fail, so a simple way to fix it is:

describe ApplicationHelper, type: :helper do
   it "generates sortable links" do
       helper.stub(:params).and_return({controller: 'users', action: 'index'})
       helper.sortable("books") #just testing out, w/o any assertions... this fails
   end
end

并像这样更新你的助手:

and update your helper like this:

module ApplicationHelper
  def sortable(column, title = nil)
    title ||= column.titleize
    direction = (column == params[:sort] && params[:direction] == "asc") ? "desc" : "asc"
    link_to title, params.merge(:sort => column, :direction => direction)
  end
end

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