code: function run() {
    var bin = path.resolve(__dirname, '../node_modules/.bin/mocha');
    var args = Array.prototype.slice.call(arguments);
    var fn = args.pop();
    var cmd = [bin].concat(args).join(' ') + ' --no-colors';
    exec(cmd, fn);
  }
docs: Runs mocha with the supplied argumentss, and passes the resulting stdout and
  stderr to the callback.
  
  @param {...string} args
  @param {function}  fn