test: refactor code in test-cluster-http-pipe

* use common.mustCall to control the functions execution automatically
* use const instead of var
* use assert.strictEqual instead assert.equal
* use assert.ifError instead of throw error
PR-URL: #10297
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: edsadr

test/parallel/test-cluster-http-pipe.js

@@ -13,28 +13,28 @@ if (common.isWindows) {
 
 if(cluster.isMaster){
 common.refreshTmpDir();
-varworker=cluster.fork();
-worker.on('message',common.mustCall(function(msg){
-assert.equal(msg,'DONE');
+constworker=cluster.fork();
+worker.on('message',common.mustCall((msg)=>{
+assert.strictEqual(msg,'DONE');
 }));
-worker.on('exit',function(){
-process.exit();
-});
+worker.on('exit',common.mustCall(()=>{}));
 return;
 }
 
-http.createServer(function(req,res){
-assert.equal(req.connection.remoteAddress,undefined);
-assert.equal(req.connection.localAddress,undefined);// TODO common.PIPE?
+http.createServer(common.mustCall((req,res)=>{
+assert.strictEqual(req.connection.remoteAddress,undefined);
+assert.strictEqual(req.connection.localAddress,undefined);
+// TODO common.PIPE?
+
 res.writeHead(200);
 res.end('OK');
-}).listen(common.PIPE,function(){
-http.get({socketPath: common.PIPE,path: '/'},function(res){
+})).listen(common.PIPE,common.mustCall(()=>{
+http.get({socketPath: common.PIPE,path: '/'},common.mustCall((res)=>{
 res.resume();
-res.on('end',function(err){
-if(err)throwerr;
+res.on('end',common.mustCall((err)=>{
+assert.ifError(err);
 process.send('DONE');
 process.exit();
-});
-});
-});
+}));
+}));
+}));