chromium/src/third_party/blink/web_tests/external/wpt/service-workers/service-worker/resources/fetch-event-add-async-worker.js

importScripts('/resources/testharness.js');

promise_test(async () => {
  await new Promise(handler => { step_timeout(handler, 0); });
  self.addEventListener('fetch', () => {});
}, 'fetch event added asynchronously does not throw');