test: refactor parallel/test-tls-pause

Use arrow functions and common.mustCall() and add a description.
PR-URL: #18714
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

Author: juggernaut451

test/parallel/test-tls-pause.js

@@ -24,6 +24,9 @@ const common = require('../common');
 if(!common.hasCrypto)
 common.skip('missing crypto');
 
+// This test ensures that the data received over tls-server after pause
+// is same as what it was sent
+
 constassert=require('assert');
 consttls=require('tls');
 constfixtures=require('../common/fixtures');
@@ -37,24 +40,23 @@ const bufSize = 1024 * 1024;
 letsent=0;
 letreceived=0;
 
-constserver=tls.Server(options,function(socket){
+constserver=tls.Server(options,common.mustCall((socket)=>{
 socket.pipe(socket);
-socket.on('data',function(c){
+socket.on('data',(c)=>{
 console.error('data',c.length);
 });
-});
+}));
 
-server.listen(0,function(){
+server.listen(0,common.mustCall(()=>{
 letresumed=false;
 constclient=tls.connect({
-port: this.address().port,
+port: server.address().port,
 rejectUnauthorized: false
-},function(){
+},common.mustCall(()=>{
 console.error('connected');
 client.pause();
 console.error('paused');
-send();
-functionsend(){
+constsend=(()=>{
 console.error('sending');
 constret=client.write(Buffer.allocUnsafe(bufSize));
 console.error(`write => ${ret}`);
@@ -69,9 +71,9 @@ server.listen(0, function() {
 resumed=true;
 client.resume();
 console.error('resumed',client);
-}
-});
-client.on('data',function(data){
+})();
+}));
+client.on('data',(data)=>{
 console.error('data');
 assert.ok(resumed);
 received+=data.length;
@@ -83,8 +85,8 @@ server.listen(0, function() {
 server.close();
 }
 });
-});
+}));
 
-process.on('exit',function(){
+process.on('exit',()=>{
 assert.strictEqual(sent,received);
 });