callbacks-in-microtasks.html | Explore in Territory

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Verify that tasks nested in microtasks can be properly tracked.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/task-ids.js"></script>
</head>
<body>
<script>

promise_test(t => {
  const scriptId = initializeTaskId();

  return scheduler.postTask(async _ => {
    // We should be in a new task.
    const postTaskId = scheduler.taskId;
    assert_equals(scriptId, postTaskId,
      "postTaskId should be equal to the script task ID.");

    let eventFired = false;
    // Set things up so the abort event listener is an ancestor of this task.
    const controller = new AbortController();
    controller.signal.onabort = t.step_func(() => {
      assert_equals(scheduler.taskId, postTaskId,
        "aborted task ID is the same as the postTask ID, as it is fired" +
        " synchronously.");
      eventFired = true;
    });

    await fetch("/resources/blank.html");
    // We're now in a new browser task that is running microtasks.
    controller.abort();
    assert_true(eventFired);
    // Make sure the previous ID was reset properly.
    assert_equals(scheduler.taskId, postTaskId);
  });
}, "Task tracking should work when a new task scope starts during a microtask");

</script>
</body>
</html>
chromium/third_party/blink/web_tests/wpt_internal/task-tracking/callbacks-in-microtasks.html
