docs: function assertFiles(expectedNumFiles, tmpDir, callback) {
      function countFiles() {
        var numFiles = 0;
        grunt.file.recurse(tmpDir, function(abspath, rootdir, subdir, filename) {
          numFiles++;
        });
        return numFiles === expectedNumFiles;
      }
  
      var interval = setInterval(function() {
        if (countFiles()) {
          clearInterval(interval);
          callback();
        }
      }, 100);
    }