node/test/parallel/test-cluster-worker-isdead.js

'use strict';
const common = require('../common');
const cluster = require('cluster');
const assert = require('assert');

if (cluster.isPrimary) {
  const worker = cluster.fork();
  let workerDead = worker.isDead();
  assert.ok(!workerDead,
            `isDead() returned ${workerDead}. isDead() should return ` +
            'false right after the worker has been created.');

  worker.on('exit', common.mustCall(() => {
    workerDead = worker.isDead();
    assert.ok(workerDead,
              `isDead() returned ${workerDead}. After an event has been ` +
              'emitted, isDead should return true');
  }));

  worker.on('message', function(msg) {
    if (msg === 'readyToDie') {
      worker.kill();
    }
  });

} else if (cluster.isWorker) {
  const workerDead = cluster.worker.isDead();
  assert.ok(!workerDead,
            `isDead() returned ${workerDead}. isDead() should return ` +
            'false when called from within a worker');
  process.send('readyToDie');
}