test: refactor test-cluster-worker-isconnected.js

PR-URL: https://github.com/nodejs/node/pull/13685
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: David Cai <davidcai1993@yahoo.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-cluster-worker-isconnected.js

@@ -1,38 +1,30 @@
 'use strict';
-require('../common');
+const common = require('../common');
 const cluster = require('cluster');
 const assert = require('assert');
 
 if (cluster.isMaster) {
   const worker = cluster.fork();
 
-  assert.ok(worker.isConnected(),
+  assert.strictEqual(worker.isConnected(), true);
-            'isConnected() should return true as soon as the worker has ' +
-            'been created.');
 
-  worker.on('disconnect', function() {
+  worker.on('disconnect', common.mustCall(() => {
-    assert.ok(!worker.isConnected(),
+    assert.strictEqual(worker.isConnected(), false);
-              'After a disconnect event has been emitted, ' +
+  }));
-              'isConncted should return false');
-  });
 
   worker.on('message', function(msg) {
     if (msg === 'readyToDisconnect') {
       worker.disconnect();
     }
   });
-
 } else {
-  assert.ok(cluster.worker.isConnected(),
+  function assertNotConnected() {
-            'isConnected() should return true from within a worker at all ' +
+    assert.strictEqual(cluster.worker.isConnected(), false);
-            'times.');
+  }
 
-  cluster.worker.process.on('disconnect', function() {
+  assert.strictEqual(cluster.worker.isConnected(), true);
-    assert.ok(!cluster.worker.isConnected(),
+  cluster.worker.on('disconnect', common.mustCall(assertNotConnected));
-              'isConnected() should return false from within a worker ' +
+  cluster.worker.process.on('disconnect', common.mustCall(assertNotConnected));
-              'after its underlying process has been disconnected from ' +
-              'the master');
-  });
 
   process.send('readyToDisconnect');
 }