test: Worker initialization failure test case

test/parallel/test-worker-init-failure.js

@@ -0,0 +1,63 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const child_process = require('child_process');
+
+// Test that workers fail with meaningful error message
+// when their initialization fails.
+
+if (common.isWindows) {
+  common.skip('ulimit does not work on Windows.');
+}
+
+// A reasonably low fd count. An empty node process
+// creates around 30 fds for its internal purposes,
+// so making it too low will crash the process early,
+// making it too high will cause too much resource use.
+const OPENFILES = 128;
+
+// Double the open files - so that some workers fail for sure.
+const WORKERCOUNT = 256;
+
+if (process.argv[2] === 'child') {
+  const { Worker } = require('worker_threads');
+  for (let i = 0; i < WORKERCOUNT; ++i) {
+    const worker = new Worker(
+      'require(\'worker_threads\').parentPort.postMessage(2 + 2)',
+      { eval: true });
+    worker.on('message', (result) => {
+      assert.strictEqual(result, 4);
+    });
+    worker.on('error', (e) => {
+      assert.match(e.message, /Worker initialization failure: EMFILE/);
+      assert.strictEqual(e.code, 'ERR_WORKER_INIT_FAILED');
+    });
+  }
+
+} else {
+  // Limit the number of open files, to force workers to fail
+  let testCmd = `ulimit -n ${OPENFILES} && `;
+
+  testCmd += `${process.execPath} ${__filename} child`;
+  const cp = child_process.exec(testCmd);
+
+  let stdout = '';
+  let stderr = '';
+
+  cp.on('exit', common.mustCall((code, signal) => {
+    assert.strictEqual(code, 0);
+    assert.strictEqual(signal, null);
+    if (stdout !== '')
+      console.log(`child stdout: ${stdout}`);
+    if (stderr !== '')
+      console.log(`child stderr: ${stderr}`);
+  }));
+
+  // Turn on the child streams for debugging purpose
+  cp.stderr.on('data', (chunk) => {
+    stdout += chunk;
+  });
+  cp.stdout.on('data', (chunk) => {
+    stderr += chunk;
+  });
+}