test: modernize test-cluster-master-error

Some stylistic changes to bring this more in line with what our tests currently look like, and add a note about general flakiness. PR-URL: #34685 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ricky Zhou <[email protected]>

Author: addaleax

test/parallel/test-cluster-master-error.js

@@ -29,16 +29,11 @@ const totalWorkers = 2;
 // Cluster setup
 if(cluster.isWorker){
 consthttp=require('http');
-http.Server(()=>{
-
-}).listen(0,'127.0.0.1');
-
+http.Server(()=>{}).listen(0,'127.0.0.1');
 }elseif(process.argv[2]==='cluster'){
-
 // Send PID to testcase process
 letforkNum=0;
 cluster.on('fork',common.mustCall(functionforkEvent(worker){
-
 // Send PID
 process.send({
 cmd: 'worker',
@@ -49,12 +44,11 @@ if (cluster.isWorker){
 if(++forkNum===totalWorkers){
 cluster.removeListener('fork',forkEvent);
 }
-}));
+},totalWorkers));
 
 // Throw accidental error when all workers are listening
 letlisteningNum=0;
 cluster.on('listening',common.mustCall(functionlisteningEvent(){
-
 // When all workers are listening
 if(++listeningNum===totalWorkers){
 // Stop listening
@@ -65,21 +59,16 @@ if (cluster.isWorker){
 thrownewError('accidental error');
 });
 }
-
-}));
+},totalWorkers));
 
 // Startup a basic cluster
 cluster.fork();
 cluster.fork();
-
 }else{
 // This is the testcase
 
 constfork=require('child_process').fork;
 
-letmasterExited=false;
-letworkersExited=false;
-
 // List all workers
 constworkers=[];
 
@@ -88,7 +77,6 @@ if (cluster.isWorker){
 
 // Handle messages from the cluster
 master.on('message',common.mustCall((data)=>{
-
 // Add worker pid to list and progress tracker
 if(data.cmd==='worker'){
 workers.push(data.workerPID);
@@ -97,30 +85,20 @@ if (cluster.isWorker){
 
 // When cluster is dead
 master.on('exit',common.mustCall((code)=>{
-
 // Check that the cluster died accidentally (non-zero exit code)
-masterExited=!!code;
+assert.strictEqual(code,1);
 
+// XXX(addaleax): The fact that this uses raw PIDs makes the test inherently
+// flaky – another process might end up being started right after the
+// workers finished and receive the same PID.
 constpollWorkers=()=>{
 // When master is dead all workers should be dead too
-letalive=false;
-workers.forEach((pid)=>alive=common.isAlive(pid));
-if(alive){
+if(workers.some((pid)=>common.isAlive(pid))){
 setTimeout(pollWorkers,50);
-}else{
-workersExited=true;
 }
 };
 
 // Loop indefinitely until worker exit
 pollWorkers();
 }));
-
-process.once('exit',()=>{
-assert(masterExited,
-'The master did not die after an error was thrown');
-assert(workersExited,
-'The workers did not die after an error in the master');
-});
-
 }