dgram: use common.mustCall and common.platformTimeout in send tests

Fixes situations were some events were not asserted to be emitted.
Removed some flakyness from tests.

test/parallel/test-dgram-send-callback-buffer-length.js

@@ -1,26 +1,24 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
 
-var dgram = require('dgram');
-var client, timer, buf, len, offset;
+const common = require('../common');
+const assert = require('assert');
 
+const dgram = require('dgram');
+const client = dgram.createSocket('udp4');
 
-client = dgram.createSocket('udp4');
-
-buf = Buffer.allocUnsafe(256);
-offset = 20;
-
-len = buf.length - offset;
+const timer = setTimeout(function() {
+  throw new Error('Timeout');
+}, common.platformTimeout(200));
 
+const buf = Buffer.allocUnsafe(256);
+const offset = 20;
+const len = buf.length - offset;
 
-client.send(buf, offset, len, common.PORT, '127.0.0.1', function(err, bytes) {
+const messageSent = common.mustCall(function messageSent(err, bytes) {
   assert.notEqual(bytes, buf.length);
   assert.equal(bytes, buf.length - offset);
   clearTimeout(timer);
   client.close();
 });
 
-timer = setTimeout(function() {
-  throw new Error('Timeout');
-}, 200);
+client.send(buf, offset, len, common.PORT, '127.0.0.1', messageSent);

test/parallel/test-dgram-send-callback-multi-buffer.js

@@ -10,23 +10,22 @@ const timer = setTimeout(function() {
   throw new Error('Timeout');
 }, common.platformTimeout(200));
 
-const onMessage = common.mustCall(function(err, bytes) {
+const messageSent = common.mustCall(function messageSent(err, bytes) {
   assert.equal(bytes, buf1.length + buf2.length);
   clearTimeout(timer);
-  client.close();
 });
 
 const buf1 = Buffer.alloc(256, 'x');
 const buf2 = Buffer.alloc(256, 'y');
 
 client.on('listening', function() {
-  client.send([buf1, buf2], common.PORT, common.localhostIPv4, onMessage);
+  client.send([buf1, buf2], common.PORT, common.localhostIPv4, messageSent);
 });
 
-client.on('message', function(buf, info) {
+client.on('message', common.mustCall(function onMessage(buf, info) {
   const expected = Buffer.concat([buf1, buf2]);
   assert.ok(buf.equals(expected), 'message was received correctly');
   client.close();
-});
+}));
 
 client.bind(common.PORT);

test/parallel/test-dgram-send-empty-array.js

@@ -15,21 +15,15 @@ const timer = setTimeout(function() {
   throw new Error('Timeout');
 }, common.platformTimeout(200));
 
-const onMessage = common.mustCall(function(err, bytes) {
-  assert.equal(bytes, 0);
+client.on('message', common.mustCall(function onMessage(buf, info) {
+  const expected = Buffer.alloc(0);
+  assert.ok(buf.equals(expected), 'message was received correctly');
   clearTimeout(timer);
   client.close();
-});
+}));
 
 client.on('listening', function() {
-  const toSend = [];
-  client.send(toSend, common.PORT, common.localhostIPv4, onMessage);
-});
-
-client.on('message', function(buf, info) {
-  const expected = Buffer.alloc(0);
-  assert.ok(buf.equals(expected), 'message was received correctly');
-  client.close();
+  client.send([], common.PORT, common.localhostIPv4);
 });
 
 client.bind(common.PORT);

test/parallel/test-dgram-send-empty-buffer.js

@@ -11,10 +11,10 @@ const client = dgram.createSocket('udp4');
 
 client.bind(common.PORT);
 
-client.on('message', function(buffer, bytes) {
+client.on('message', common.mustCall(function onMessage(buffer, bytes) {
   clearTimeout(timer);
   client.close();
-});
+}));
 
 const buf = Buffer.alloc(0);
 client.send(buf, 0, 0, common.PORT, '127.0.0.1', function(err, len) { });

test/parallel/test-dgram-send-multi-buffer-copy.js

@@ -13,7 +13,6 @@ const timer = setTimeout(function() {
 const onMessage = common.mustCall(function(err, bytes) {
   assert.equal(bytes, buf1.length + buf2.length);
   clearTimeout(timer);
-  client.close();
 });
 
 const buf1 = Buffer.alloc(256, 'x');
@@ -25,10 +24,10 @@ client.on('listening', function() {
   toSend.splice(0, 2);
 });
 
-client.on('message', function(buf, info) {
+client.on('message', common.mustCall(function onMessage(buf, info) {
   const expected = Buffer.concat([buf1, buf2]);
   assert.ok(buf.equals(expected), 'message was received correctly');
   client.close();
-});
+}));
 
 client.bind(common.PORT);