anchor.diff:    var dir = new Directory("").createTempSync();
     _sandboxDir = dir.path;
   
  +  // TODO(rnystrom): Temporary while debugging the Windows bot.
  +  print("create mock modtime map for $_sandboxDir");
  +
     _mockFileModificationTimes = new Map<String, int>();
     mockGetModificationTime((path) {
       path = p.relative(path, from: _sandboxDir);
  
positive.code:   schedule(() {
      new File(p.join(_sandboxDir, from)).renameSync(p.join(_sandboxDir, to));
  
      // Manually update the mock modification time for the file.
      var milliseconds = _mockFileModificationTimes.putIfAbsent(to, () => 0);
      _mockFileModificationTimes[to]++;
    });
  }
  
  
negative.code:     // Make sure we got a path in the sandbox.
      assert(p.isRelative(path)  && !path.startsWith(".."));
  
      // TODO(rnystrom): Temporary while debugging the Windows bot.
      print("get mock modtime for $path = ${_mockFileModificationTimes[path]}");
      return new DateTime.fromMillisecondsSinceEpoch(
          _mockFileModificationTimes[path]);
    });
  
    // Delete the sandbox when done.
    currentSchedule.onComplete.schedule(() {
      // TODO(rnystrom): Temporary while debugging the Windows bot.
      print("delete mock modtime map for $_sandboxDir");
  
      if (_sandboxDir != null) {
        new Directory(_sandboxDir).deleteSync(recursive: true);
        _sandboxDir = null;
  