diff --git a/test/report/test-report-worker.js b/test/report/test-report-worker.js
index a34c05f08431de..39a2c87f65f044 100644
--- a/test/report/test-report-worker.js
+++ b/test/report/test-report-worker.js
@@ -23,6 +23,7 @@ async function basic() {
   helper.validateContent(report);
   assert.strictEqual(report.workers.length, 1);
   helper.validateContent(report.workers[0]);
+  assert.strictEqual(report.workers[0].header.threadId, w.threadId);
 
   w.postMessage({});