diff --git a/test/parallel/test-worker-onmessage.js b/test/parallel/test-worker-onmessage.js
index f315b0d2019a9a..3ed10755cece28 100644
--- a/test/parallel/test-worker-onmessage.js
+++ b/test/parallel/test-worker-onmessage.js
@@ -7,13 +7,20 @@ const { Worker, parentPort } = require('worker_threads');
 if (!process.env.HAS_STARTED_WORKER) {
   process.env.HAS_STARTED_WORKER = 1;
   const w = new Worker(__filename);
+  const expectation = [ 4, undefined, null ];
+  const actual = [];
   w.on('message', common.mustCall((message) => {
-    assert.strictEqual(message, 4);
-    w.terminate();
-  }));
+    actual.push(message);
+    if (actual.length === expectation.length) {
+      assert.deepStrictEqual(expectation, actual);
+      w.terminate();
+    }
+  }, expectation.length));
   w.postMessage(2);
 } else {
   parentPort.onmessage = common.mustCall((message) => {
     parentPort.postMessage(message.data * 2);
+    parentPort.postMessage(undefined);
+    parentPort.postMessage(null);
   });
 }