anchor.diff:        });
   }
   
  -final WhiteSpaceExp = new RegExp(r'\s+', multiLine: true);
  -final LsTreeExp = new RegExp(r'^(\d+)\s+(\w+)\s+(\w+)\s+([\w\/]+)');
  +final _whiteSpaceExp = new RegExp(r'\s+', multiLine: true);
  
positive.code: 
  String _getParentTree(ProcessResult pr) {
    require(pr.exitCode == 0, 'cat-file returned an error');
    final split = pr.stdout.split(WhiteSpaceExp);
    require(split[0] == 'tree', "Should be a tree");
    return split[1].trim();
  }
  
negative.code: 
  Future<bool> _fromSourceDirTree(TaskContext ctx, String tree,
      String targetBranch, String sourceDir, String sourceBranch) {
    final split = tree.split(_whiteSpaceExp);
    final sha = split[2];
  
    final gitArgs = new List<String>.from(['commit-tree', sha]);
    final branchNameRef = 'refs/heads/$targetBranch';
  