speculation-rules/prerender/workers.html

<!DOCTYPE html>
<title>Same-origin prerendering can access localStorage</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="/common/dispatcher/dispatcher.js"></script>
<script src="resources/utils.js"></script>
<body>
<script>

setup(() => assertSpeculationRulesIsSupported());

promise_test(async t => {
  const {exec, activate} = await create_prerendered_page(t);
  const workerURL = new URL('resources/worker-post-timeOrigin.js', location.href).toString();
  await exec(workerURL => {
    window.worker = new Worker(workerURL);
    window.waitForWorker = new Promise(resolve => worker.addEventListener('message', e => {
        resolve({
          prerendering: document.prerendering,
          activationStart: performance.getEntriesByType('navigation')[0].activationStart,
          workerLoad: performance.getEntriesByName(workerURL)[0].startTime,
          workerStart: e.data});
    }), workerURL);
  }, workerURL);

  // We want to prevent false success by waiting for enough time to make sure the worker is not
  // yet initialized
  await new Promise(resolve => t.step_timeout(resolve, 500));
  await activate();
  const {workerStart, activationStart, workerLoad, prerendering } = await exec(() => window.waitForWorker);
  assert_equals(prerendering, false);
  assert_greater_than(activationStart, workerLoad, "Loading the worker script should not be delayed");
  assert_greater_than(workerStart, activationStart, "Starting the worker should be delayed");
}, "Dedicated workers should be loaded in suspended state until activated");

promise_test(async t => {
  const {exec, activate} = await create_prerendered_page(t);
  const workerURL = new URL(`resources/shared-worker.py?id=${token()}`, location.href).toString();
  await exec(workerURL => {
    window.worker = new SharedWorker(workerURL, 'dummy');
    window.worker.port.start();
    window.waitForSharedWorkerLoadingReport =
      fetch(workerURL + "&check=true")
        .then(r => t.text())
        .then(text => text === 'ok' && document.prerendering);
    window.waitForWorker = new Promise(resolve => worker.port.addEventListener('message', e => {
        resolve({
          prerendering: document.prerendering,
          activationStart: performance.getEntriesByType('navigation')[0].activationStart,
          workerStart: e.data});
    }), workerURL);
  }, workerURL);

  await new Promise(resolve => t.step_timeout(resolve, 300));
  await activate();
  const {workerStart, activationStart, workerLoad, prerendering } = await exec(() => window.waitForWorker);
  const loadedWhilePrerendering = await exec(() => window.loadedWhilePrerendering);
  assert_true(loadedWhilePrerendering, "The shared worker should be loaded (but suspended) while prerendering");
  assert_false(prerendering, "SharedWorker should be suspended until activated");
  assert_greater_than(workerStart, activationStart, "Starting the worker should be delayed");
  // TODO: check SharedWorker loading. This is not yet possible due to SharedWorkers not reporting timing.
}, "Shared workers should be loaded in suspended state until activated");

promise_test(async t => {
  const {exec, activate} = await create_prerendered_page(t);
  const workerURL = new URL(`resources/shared-worker.py?id=${token()}`, location.href).toString();
  const workerStartTime1 = await new Promise(resolve => {
    const worker = new SharedWorker(workerURL, 'worker');
    worker.port.start();
    worker.port.addEventListener('message', e => resolve(e.data));
  });

  await exec(workerURL => {
    window.worker = new SharedWorker(workerURL, 'worker');
    window.worker.port.start();
    window.waitForWorker = new Promise(resolve => worker.port.addEventListener('message', e => {
        resolve({
          prerendering: document.prerendering,
          activationStart: performance.getEntriesByType('navigation')[0].activationStart,
          workerStartTime2: e.data});
    }), workerURL);
  }, workerURL);

  await new Promise(resolve => t.step_timeout(resolve, 300));
  await activate();
  const {workerStartTime2, activationStart, workerLoad, prerendering } = await exec(() => window.waitForWorker);
  assert_true(prerendering, "An existing SharedWorker should be accessible while prerendering");
  assert_equals(workerStartTime1, workerStartTime2);
  assert_greater_than(workerStart, activationStart, "Starting the worker should be delayed");
}, "Existing shared workers should be accessible before activation");

</script>
</body>