anchor.diff:    io.ProcessResult pubListResult;
   
     void setPubListError() {
  -    pubListResult = new io.ProcessResult(0, 1, '', 'ERROR');
  +    pubListResult = new _MockProcessResult(0, 1, '', 'ERROR');
     }
   
     void setPubListResult({Map<String, String> packages: const {},
         List<String> input_files: const []}) {
  -    pubListResult = new io.ProcessResult(0, 0,
  +    pubListResult = new _MockProcessResult(0, 0,
           JSON.encode({'packages': packages, 'input_files': input_files}), '');
     }
   
  
positive.code: 
    test_computePackageMap_noPreviousInfo_pubListError() {
      String pubspecLock = posix.join(projectFolder.path, 'pubspec.lock');
      String pkgName = 'foo';
      String pkgPath = '/pkg/foo';
      setPubListError();
      OptimizingPubPackageMapInfo info =
          provider.computePackageMap(projectFolder);
  
negative.code:     return pubListResult;
    }
  }
  
  class _MockProcessResult implements io.ProcessResult {
    @override
    final int pid;
  
    @override
    final int exitCode;
  
    @override
    final stdout;
  
    @override
    final stderr;
  
    _MockProcessResult(this.pid, this.exitCode, this.stdout, this.stderr);
  }
  