back-forward-cache-restoration.tentative.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /performance-timeline/back-forward-cache-restoration.tentative.html - WPT Dashboard Interop Dashboard

<!doctype html>

<html>

<head>

  <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="/html/browsers/browsing-the-web/back-forward-cache/resources/helper.sub.js"></script>

</head>

<body>

  <script>

    const BackForwardCacheRestorationName = '';

    const BackForwardCacheRestorationType = 'back-forward-cache-restoration';

    let getNavigationId = (i) => {

      let identifier = 'mark' + i;

      performance.mark(identifier);

      return window.performance.getEntriesByName(identifier)[0].navigationId;

    let getNumberofBackForwardCacheRestorationEntries = (BackForwardCacheRestorationType) => {

      return window.performance.getEntriesByType(BackForwardCacheRestorationType).length;

    let getBackForwardCacheRestorationByType = (BackForwardCacheRestorationType) => {

      let entries = window.performance.getEntriesByType(BackForwardCacheRestorationType);

      return entries[entries.length - 1];

    let getBackForwardCacheRestorationByGetAllAndFilter = (BackForwardCacheRestorationType) => {

      let entries = window.performance.getEntries().filter(e => e.entryType == BackForwardCacheRestorationType);

      return entries[entries.length - 1];

    let getBackForwardCacheRestorationByPerformanceObserverBuffered = async (BackForwardCacheRestorationType) => {

      let p = new Promise(resolve => {

        new PerformanceObserver((list) => {

          const entries = list.getEntries().filter(e => e.entryType == BackForwardCacheRestorationType);

          if (entries.length > 0) {

            resolve(entries[entries.length - 1]);

        }).observe({ type: BackForwardCacheRestorationType, buffered: true });

});

      return await p;

    let checkEntry = (entry, previousNavigationId) => {

      assert_equals(entry.name, BackForwardCacheRestorationName);

      assert_equals(entry.entryType, BackForwardCacheRestorationType);

      assert_not_equals(entry.navigationId, previousNavigationId);

      assert_true(entry.pageshowEventStart > entry.startTime);

      assert_true(entry.pageshowEventEnd >= entry.pageshowEventStart);

    promise_test(async t => {

      const pageA = new RemoteContext(token());

      const pageB = new RemoteContext(token());

      const urlA = executorPath + pageA.context_id;

      const urlB = originCrossSite + executorPath + pageB.context_id;

      // Open url A.

      window.open(urlA, '_blank', 'noopener');

      await pageA.execute_script(waitForPageShow);

      // Assert no instance of BackForwardCacheRestoration exists without back forward cache navigatoin.

      let size = await pageA.execute_script(getNumberofBackForwardCacheRestorationEntries);

      assert_equals(0, size);

      let entry;

      for (i = 0; i < 2; i++) {

        let curr_nav_id = await pageA.execute_script(getNavigationId, [i]);

        // Navigate away to url B and back.

        await navigateAndThenBack(pageA, pageB, urlB);

        // Assert Performance Observer API supports BackForwardCacheRestoration.

        entry = await pageA.execute_script(getBackForwardCacheRestorationByPerformanceObserverBuffered, [BackForwardCacheRestorationType]);

        // The navigation id after a bfcache restoration should be different

        // from that before.

        checkEntry(entry, curr_nav_id);

        // Assert Performance Timeline API supports BackForwardCacheRestoration.

        entry = await pageA.execute_script(getBackForwardCacheRestorationByType, [BackForwardCacheRestorationType]);

        checkEntry(entry, curr_nav_id);

        entry = await pageA.execute_script(getBackForwardCacheRestorationByGetAllAndFilter, [BackForwardCacheRestorationType]);

        checkEntry(entry, curr_nav_id);

    }, 'Performance API for the back forward cache restoration entry.');

  </script>

</body>

</html>