test_suppressed_microtasks.html

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<!DOCTYPE HTML>

<html>

<head>

  <meta charset="utf-8">

  <title>Test microtask suppression</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>

  <script>

    SimpleTest.waitForExplicitFinish();

    var previousTask = -1;

    function test() {

      let win = window.open("about:blank");

      win.onload = function() {

        win.onmessage = function() {

          win.start = win.performance.now();

          win.didRunMicrotask = false;

          win.onmessage = function() {

            ok(win.didRunMicrotask, "Should have run a microtask.");

            let period = win.performance.now() - win.start;

            win.opener.ok(

              period < 200,

              "Running a task should be fast. Took " + period + "ms.");

            win.onmessage = null;

          win.queueMicrotask(function() { win.didRunMicrotask = true; });

          win.postMessage("measurementMessage", "*");

        win.postMessage("initialMessage", "*");

        const last = 500000;

        for (let i = 0; i < last + 1; ++i) {

          window.queueMicrotask(function() {

            // Check that once microtasks are unsuppressed, they are handled in

            // the correct order.

            if (previousTask !=  i - 1) {

              // Explicitly optimize out cases which pass.

              ok(false, "Microtasks should be handled in order.");

            previousTask = i;

            if (i == last) {

              win.close();

              SimpleTest.finish();

});

        // Synchronous XMLHttpRequest suppresses microtasks.

        var xhr = new XMLHttpRequest();

        xhr.open("GET", "slow.sjs", false);

        xhr.send();

        is(previousTask, -1, "Shouldn't have run microtasks during a sync XHR.");

  </script>

</head>

<body onload="test()">

<p id="display"></p>

<div id="content" style="display: none"></div>

<pre id="test"></pre>

</body>

</html>