longtask-promise.html

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This test has a WPT meta file that expects 4 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /longtask-timing/longtask-promise.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<meta charset=utf-8>

<title>LongTask Timing: Promise resolvers</title>

<body>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="resources/utils.js"></script>

<h1>Long Task: promise resolvers</h1>

<script>

  function test_promise_long_task(name, promise) {

    promise_test(async t => {

      assert_implements(window.PerformanceLongTaskTiming, 'Longtasks are not supported.');

      const longTaskPromise = new Promise(resolve => {

        const observer = new PerformanceObserver(t.step_func(entryList => {

          observer.disconnect();

          resolve(entryList.getEntries());

        }));

        observer.observe({entryTypes: ['longtask']});

});

      await promise().catch(() => {});

      busyWait();

      const entries = await longTaskPromise;

      assert_greater_than_equal(entries.length, 1);

    }, `Performance longtask entries after a promise: ${name}`);

  test_promise_long_task("successful fetch", () => fetch("/common/dummy.xml"));

  test_promise_long_task("Response.text()", () =>

    fetch("/common/dummy.xml").then(r => r.text()));

  test_promise_long_task("rejected fetch", () => fetch("/common/non-existent.xml"));

  test_promise_long_task("JSON error", () => fetch("/common/dummy.xml").then(r => r.json()));

</script>

</body>