anchor.diff:    } else {
       return stack.toString();
     }
  - 
  -  // Calculate the max width of first column so we can 
  +
  +  // Calculate the max width of first column so we can
     // pad to align the second columns.
     int padding = lines.fold(0, (n, line) {
       var match = _frameRegExp.firstMatch(line);
  
positive.code:  *  * __Checks__: Test expectations can be specified via [expect]
   *  * __Matchers__: [expect] assertions are written declaratively using the
   *    [Matcher] class.
   *  * __Configuration__: The framework can be adapted by calling [configure] with a
   *    [Configuration]. See the other libraries in the `unittest` package for
   *    alternative implementations of [Configuration] including
   *    `compact_vm_config.dart`, `html_config.dart` and
   *    `html_enhanced_config.dart`.
   *
   * ##Examples##
  
negative.code: 
  // Stack formatting utility. Strips extraneous content from a stack trace.
  // Stack frame lines are parsed with a regexp, which has been tested
  // in Chrome, Firefox and the VM. If a line fails to be parsed it is
  // included in the output to be conservative.
  //
  // The output stack consists of everything after the call to TestCase._run.
  