anchor.diff:  
   :marked
     The _karma_ watcher detects the change to the compilation output and re-runs the test.
  +
  +  **`Karma`**监视器检测到编译器输出的变化，并重新运行测试。
  +
   code-example(format="." language="bash").
     [1] Chrome 51.0.2704: Executed 0 of 1 SUCCESS
         Chrome 51.0.2704 1st tests true is true FAILED
  
positive.code:         An optional file that supplements the SystemJS configuration in `systemjs.config.js` with
          configuration for the specific needs of the application itself.
  
          A stock `systemjs.config.js` can't anticipate those needs. 
          You fill the gaps here.
  
          The sample version for this chapter adds the **model barrel**
          to the SystemJs `packages` configuration.
    tr
      td(colspan="2") 
        +makeExample('testing/ts/systemjs.config.extras.js', '', 'systemjs.config.extras.js')(format='.')
   
  :marked
    ### npm packages
  
    The sample tests are written to run in Jasmine and karma.
    The two "fast path" setups added the appropriate Jasmine and karma npm packages to the 
    `devDependencies` section of the `package.json`.
    They were installed when you ran `npm install`.
  
  .l-hr
  a#1st-karma-test
  :marked
    # The first karma test
  
    Start with a simple test to make sure the setup works properly.
  
    Create a new file called `1st.spec.ts` in the application root folder, `app/`
  
  .alert.is-important
    :marked
  
negative.code:   Both the compiler and karma continue to run. The compiler output is preceeded by `[0]`; 
    the karma output by `[1]`.
  
    编译器和`Karma`都会持续运行。编译器的输入信息前面有`[0]`，`Karma`的输出前面有`[1]`。
  
    Change the expectation from `true` to `false`.
  
    将期望从`true`变换为`false`。
  
    The _compiler_ watcher detects the change and recompiles.
  
    **编译器**监视器检测到这个变化并重新编译。
  
  code-example(format="." language="bash").
    [0] 1:49:21 PM - File change detected. Starting incremental compilation...
  