code: function SingleResponseCB (data) {
      switch (data.status ) {
          case -1: console.log (" SMS Fail to Send SMS");
              break;
          case -2: console.log (" SMS Timeout waiting acknowledgement");
              break;
          case 1: console.log (" SMS  Message Sent");
              break;
          case 2: console.log (" SMS  Acknowledgement=[%s]", data.msg.ack);
              break;
          default:
      }
      // quit except if we wait for ack [leave some time to DB to close operation]
      if (data.status <= 0)  setTimeout (process.exit, 1000);
  }
docs: Minimal Unit Testing Method