Worker-creation-happens-in-parallel.https.html

<!DOCTYPE html>
<title>Test that creation of a "new Worker()" will occur in parallel to the main JS thread performing other computation, and can be joined with.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
promise_test(t => {
  return new Promise(resolve => {
    let worker = new Worker("support/Worker-creation-happens-in-parallel.js");
    let sab = new Uint8Array(new SharedArrayBuffer(16));
    window.sab = sab;
    worker.postMessage(sab);
    let end = performance.now() + 10*1000;
    while(sab[0] != 1 && performance.now() < end) /*wait to join with the result*/;
    assert_true(sab[0] == 1);
    resolve();
  });
}, 'Tests that creation of a "new Worker()" will occur in parallel');
</script>

chromium/third_party/blink/web_tests/external/wpt/workers/Worker-creation-happens-in-parallel.https.html