Nokogiri刮擦测试失败？

Question

我有以下代码：

  url       = "http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dpets&field-keywords="
  data      = Nokogiri::HTML(open(url))

  department   = data.css('#ref_2619534011')

  @department_hash = {}
  department.css('li').drop(1).each do | department |
    department_title = department.css('.refinementLink').text
    department_count = department.css('.narrowValue').text[/[\d,]+/].delete(",").to_i
    @department_hash[:department] ||= {}
    @department_hash[:department]["Pet Supplies"] ||= {}
    @department_hash[:department]["Pet Supplies"][department_title] = department_count
  end 

所以当我在模板中执行<%= @department_hash %> 时，我会得到：

{:department=>{"Pet Supplies"=>{"Birds"=>15918, "Cats"=>245418, "Dogs"=>513869, "Fish & Aquatic Pets"=>47182, "Horses"=>14774, "Insects"=>358, "Reptiles & Amphibians"=>5834, "Small Animals"=>19806}}} 

我为app.rb 创建了一个规范（我正在使用 Sinatra）：

app_spec.rb：

require File.dirname(__FILE__) + '/app.rb'

describe "Department" do
  it "should scrap correct string" do
    expect(@department_hash).to eq '{:department=>{"Pet Supplies"=>{"Birds"=>15918, "Cats"=>245418, "Dogs"=>513869, "Fish & Aquatic Pets"=>47182, "Horses"=>14774, "Insects"=>358, "Reptiles & Amphibians"=>5834, "Small Animals"=>19806}}}' 
  end
end

但测试失败：

  1) Department should scrap correct string
     Failure/Error: expect(@department_hash).to eq '{:department=>{"Pet Supplies"=>{"Birds"=>15918, "Cats"=>245418, "Dogs"=>513869, "Fish & Aquatic Pets"=>47182, "Horses"=>14774, "Insects"=>358, "Reptiles & Amphibians"=>5834, "Small Animals"=>19806}}}'

       expected: "{:department=>{\"Pet Supplies\"=>{\"Birds\"=>15918, \"Cats\"=>245418, \"Dogs\"=>513869, \"Fish & Aquatic Pets\"=>47182, \"Horses\"=>14774, \"Insects\"=>358, \"Reptiles & Amphibians\"=>5834, \"Small Animals\"=>19806}}}"
            got: nil

       (compared using ==)
     # ./app_spec.rb:5:in `block (2 levels) in <top (required)>'

编辑：

我试过了：

expect(@department_hash[:department]["宠物用品"].keys).to eq '[“鸟”、“猫”、“狗”、“鱼和水生宠物”、“马”、“昆虫”、 “爬行动物和两栖动物”、“小动物”]'

但测试也失败了：

2) 部门应废弃正确的密钥 失败/错误：expect(@department_hash[:department]["Pet Supplies"].keys).to eq '["Birds", "Cats", "Dogs", "Fish & Aquatic 宠物”、“马”、“昆虫”、“爬行动物和两栖动物”、“小动物”]' 无方法错误： '

中未定义的方法[]' for nil:NilClass # ./app_spec.rb:9:inblock（2 级）

可能是什么原因？

Answer 1

@department_hash 未定义在测试范围内。

举个简单的例子：

require 'rspec/autorun'

@department_hash = 2
puts defined?(@department_hash)
#=> "instance-variable"

describe "Department" do
  it "should scrap correct string" do
        puts defined?(@department_hash)
        #=> "" (ie not defined)
    end
end

可以看到@department_hash是在main里面定义的，但是在test里面没有定义。

您需要在测试范围内运行您的应用代码。例如，将代码移动到测试中，@department_hash 将不再为 nil。

require 'rspec/autorun'
require 'nokogiri'
require 'open-uri'

describe "Department" do
  it "should scrap correct string" do
    url       = "http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dpets&field-keywords="
    data      = Nokogiri::HTML(open(url))

    department   = data.css('#ref_2619534011')

    @department_hash = {}
    department.css('li').drop(1).each do | department |
      department_title = department.css('.refinementLink').text
      department_count = department.css('.narrowValue').text[/[\d,]+/].delete(",").to_i
      @department_hash[:department] ||= {}
      @department_hash[:department]["Pet Supplies"] ||= {}
      @department_hash[:department]["Pet Supplies"][department_title] = department_count
    end       

    expect(@department_hash).to eq({:department=>{"Pet Supplies"=>{"Birds"=>17556, "Cats"=>245692, "Dogs"=>516246, "Fish & Aquatic Pets"=>47424, "Horses"=>15062, "Insects"=>358, "Reptiles & Amphibians"=>5835, "Small Animals"=>19836}}})
  end
end

请注意，您的测试应该是eq(hash) 而不是eq 'hash'（即您想要比较散列而不是字符串与散列。

更新 - 提取到类的代码：

将应用程序代码移到测试中并不理想，如果它是为了在其他地方可重用。相反，最好为您的应用程序代码创建一个方法或类，然后从测试中调用该代码。

require 'rspec/autorun'
require 'nokogiri'
require 'open-uri'

# This class could be placed in your app.rb  
class DepartmentScraper
  def scrape_page()
    url       = "http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dpets&field-keywords="
    data      = Nokogiri::HTML(open(url))

    department   = data.css('#ref_2619534011')

    @department_hash = {}
    department.css('li').drop(1).each do | department |
      department_title = department.css('.refinementLink').text
      department_count = department.css('.narrowValue').text[/[\d,]+/].delete(",").to_i
      @department_hash[:department] ||= {}
      @department_hash[:department]["Pet Supplies"] ||= {}
      @department_hash[:department]["Pet Supplies"][department_title] = department_count        
    end

    return @department_hash
  end
end

describe "Department" do
  it "should scrap correct string" do
    department_hash = DepartmentScraper.new.scrape_page()

    expect(department_hash).to eq({:department=>{"Pet Supplies"=>{"Birds"=>17556, "Cats"=>245692, "Dogs"=>516246, "Fish & Aquatic Pets"=>47424, "Horses"=>15062, "Insects"=>358, "Reptiles & Amphibians"=>5835, "Small Animals"=>19836}}})
  end
end