anchor.diff:  a#setup
   :marked
     # Setup
  +  
  +  # 搭建测试环境
   
     Many think writing tests is fun. 
     Few enjoy setting up the test environment.
  
positive.code:   the deep details of setup appear later in the chapter (_forthcoming_).
    A bare minimum of discussion plus the downloadable source code must suffice for now.
  
    There are two fast paths to getting started.
    1. Start a new project following the instructions in the 
    [QuickStart github repository](https://github.com/angular/quickstart/blob/master/README.md).
  
    1. Start a new project with the 
    [Angular CLI](https://github.com/angular/angular-cli/blob/master/README.md).
  
    Both approaches install **npm packages, files, and scripts** pre-configured for applications
    built in their respective modalities. 
    Their artifacts and procedures differ slightly but their essentials are the same 
    and there are no differences in the test code.
  
    In this chapter, the application and its tests are based on the QuickStart repo.
  
  .alert.is-helpful
    :marked
      If youur application was based on the QuickStart repository,
      you can skip the rest of this section and get on with your first test.
      The QuickStart repo provides all necessary setup.
  
  :marked
    Here's brief description of the setup files.
   
  table(width="100%")
    col(width="20%")
    col(width="80%") 
    tr
      th File
      th Description
    tr
      td(style="vertical-align: top") <code>karma.conf.js</code>
      td
  
negative.code:         which application and test files to load, which browser(s) to use,
          and how to report test results.
  
          Karma配置文件。它指定使用哪些插件、加载哪个应用和测试文件、使用哪些浏览器和如何报告测试结果。
  
          It loads three other setup files:
  
          它加载三种配置文件：
  
          * `systemjs.config.js` 
          * `systemjs.config.extras.js`
          * `karma-test-shim.js`
  