1'use strict'; 2const common = require('../common'); 3const mustCall = common.mustCall; 4const assert = require('assert'); 5const dgram = require('dgram'); 6const dns = require('dns'); 7 8const socket = dgram.createSocket('udp4'); 9const buffer = Buffer.from('gary busey'); 10 11dns.setServers([]); 12 13socket.once('error', onEvent); 14 15// assert that: 16// * callbacks act as "error" listeners if given. 17// * error is never emitter for missing dns entries 18// if a callback that handles error is present 19// * error is emitted if a callback with no argument is passed 20socket.send(buffer, 0, buffer.length, 100, 21 'dne.example.com', mustCall(callbackOnly)); 22 23function callbackOnly(err) { 24 assert.ok(err); 25 socket.removeListener('error', onEvent); 26 socket.on('error', mustCall(onError)); 27 socket.send(buffer, 0, buffer.length, 100, 'dne.invalid'); 28} 29 30function onEvent(err) { 31 assert.fail(`Error should not be emitted if there is callback: ${err}`); 32} 33 34function onError(err) { 35 assert.ok(err); 36 socket.close(); 37} 38