test: cleanup test-net-server-address.js

Refactored test:
- 'var' to 'const'
- functon to arrow function
- using common.mustCall() and common.fail()

PR-URL: https://github.com/nodejs/node/pull/8586
Reviewed-By: Yosuke Furukawa <yosuke.furukawa@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/sequential/test-net-server-address.js

@@ -1,23 +1,22 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
-var net = require('net');
+const common = require('../common');
+const assert = require('assert');
+const net = require('net');
 
 // Test on IPv4 Server
-var family_ipv4 = 'IPv4';
-var server_ipv4 = net.createServer();
+const family_ipv4 = 'IPv4';
+const server_ipv4 = net.createServer();
 
-server_ipv4.on('error', function(e) {
-  console.log('Error on ipv4 socket: ' + e.toString());
-});
+server_ipv4.on('error', common.fail);
 
-server_ipv4.listen(common.PORT, common.localhostIPv4, function() {
-  var address_ipv4 = server_ipv4.address();
+server_ipv4
+  .listen(common.PORT + 1, common.localhostIPv4, common.mustCall(() => {
+    const address_ipv4 = server_ipv4.address();
     assert.strictEqual(address_ipv4.address, common.localhostIPv4);
-  assert.strictEqual(address_ipv4.port, common.PORT);
+    assert.strictEqual(address_ipv4.port, common.PORT + 1);
     assert.strictEqual(address_ipv4.family, family_ipv4);
     server_ipv4.close();
-});
+  }));
 
 if (!common.hasIPv6) {
   common.skip('ipv6 part of test, no IPv6 support');
@@ -25,65 +24,57 @@ if (!common.hasIPv6) {
 }
 
 // Test on IPv6 Server
-var localhost_ipv6 = '::1';
-var family_ipv6 = 'IPv6';
-var server_ipv6 = net.createServer();
+const localhost_ipv6 = '::1';
+const family_ipv6 = 'IPv6';
+const server_ipv6 = net.createServer();
 
-server_ipv6.on('error', function(e) {
-  console.log('Error on ipv6 socket: ' + e.toString());
-});
+server_ipv6.on('error', common.fail);
 
-server_ipv6.listen(common.PORT, localhost_ipv6, function() {
-  var address_ipv6 = server_ipv6.address();
+server_ipv6.listen(common.PORT + 2, localhost_ipv6, common.mustCall(() => {
+  const address_ipv6 = server_ipv6.address();
   assert.strictEqual(address_ipv6.address, localhost_ipv6);
-  assert.strictEqual(address_ipv6.port, common.PORT);
+  assert.strictEqual(address_ipv6.port, common.PORT + 2);
   assert.strictEqual(address_ipv6.family, family_ipv6);
   server_ipv6.close();
-});
+}));
 
 // Test without hostname or ip
-var anycast_ipv6 = '::';
-var server1 = net.createServer();
+const anycast_ipv6 = '::';
+const server1 = net.createServer();
 
-server1.on('error', function(e) {
-  console.log('Error on ip socket: ' + e.toString());
-});
+server1.on('error', common.fail);
 
 // Specify the port number
-server1.listen(common.PORT, function() {
-  var address = server1.address();
+server1.listen(common.PORT + 3, common.mustCall(() => {
+  const address = server1.address();
   assert.strictEqual(address.address, anycast_ipv6);
-  assert.strictEqual(address.port, common.PORT);
+  assert.strictEqual(address.port, common.PORT + 3);
   assert.strictEqual(address.family, family_ipv6);
   server1.close();
-});
+}));
 
 // Test without hostname or port
-var server2 = net.createServer();
+const server2 = net.createServer();
 
-server2.on('error', function(e) {
-  console.log('Error on ip socket: ' + e.toString());
-});
+server2.on('error', common.fail);
 
 // Don't specify the port number
-server2.listen(function() {
-  var address = server2.address();
+server2.listen(common.mustCall(() => {
+  const address = server2.address();
   assert.strictEqual(address.address, anycast_ipv6);
   assert.strictEqual(address.family, family_ipv6);
   server2.close();
-});
+}));
 
 // Test without hostname, but with a false-y port
-var server3 = net.createServer();
+const server3 = net.createServer();
 
-server3.on('error', function(e) {
-  console.log('Error on ip socket: ' + e.toString());
-});
+server3.on('error', common.fail);
 
 // Specify a false-y port number
-server3.listen(0, function() {
-  var address = server3.address();
+server3.listen(0, common.mustCall(() => {
+  const address = server3.address();
   assert.strictEqual(address.address, anycast_ipv6);
   assert.strictEqual(address.family, family_ipv6);
   server3.close();
-});
+}));