test: fix flaky test-net-socket-timeout-unref

Throw immediately on socket timeout rather than checking boolean in exit
handler.
PR-URL: #6003Fixes: #5128
Reviewed-By: Myles Borins <myles.borins@gmail.com>

Author: Trott

test/parallel/test-net-socket-timeout-unref.js

@@ -1,39 +1,35 @@
 'use strict';
-varcommon=require('../common');
-varassert=require('assert');
-varnet=require('net');
 
-varserver=net.createServer(function(c){
+// Test that unref'ed sockets with timeouts do not prevent exit.
+
+constcommon=require('../common');
+constnet=require('net');
+
+constserver=net.createServer(function(c){
 c.write('hello');
 c.unref();
 });
 server.listen(common.PORT);
 server.unref();
 
-vartimedout=false;
 varconnections=0;
-varsockets=[];
-vardelays=[8,5,3,6,2,4];
+constsockets=[];
+constdelays=[8,5,3,6,2,4];
 
 delays.forEach(function(T){
-varsocket=net.createConnection(common.PORT,'localhost');
-socket.on('connect',function(){
+constsocket=net.createConnection(common.PORT,'localhost');
+socket.on('connect',common.mustCall(function(){
 if(++connections===delays.length){
 sockets.forEach(function(s){
-s[0].setTimeout(s[1]*1000,function(){
-timedout=true;
-s[0].destroy();
+s.socket.setTimeout(s.timeout,function(){
+s.socket.destroy();
+thrownewError('socket timed out unexpectedly');
 });
 
-s[0].unref();
+s.socket.unref();
 });
 }
-});
-
-sockets.push([socket,T]);
-});
+}));
 
-process.on('exit',function(){
-assert.strictEqual(timedout,false,
-'Socket timeout should not hold loop open');
+sockets.push({socket: socket,timeout: T*1000});
 });