<!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>
