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Test Info: Warnings
- This test gets skipped with pattern: os == 'linux' && os_version == '22.04' && display == 'wayland'
- Manifest: gfx/layers/apz/test/mochitest/mochitest.toml
<!DOCTYPE HTML>
<html>
<!--
-->
<head>
  <script src="/tests/SimpleTest/SimpleTest.js"></script>
  <script src="/tests/SimpleTest/EventUtils.js"></script>
  <script src="/tests/SimpleTest/paint_listener.js"></script>
  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>
  <script type="application/javascript" src="apz_test_utils.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
  <style>
  #outer-frame {
      height: 500px;
      overflow: scroll;
      background: repeating-linear-gradient(#CCC, #CCC 100px, #BBB 100px, #BBB 200px);
  }
  #inner-frame {
      margin-top: 25%;
      height: 200%;
      width: 75%;
      overflow: scroll;
  }
  #inner-content {
      height: 200%;
      width: 200%;
      background: repeating-linear-gradient(#EEE, #EEE 100px, #DDD 100px, #DDD 200px);
  }
  </style>
</head>
<body>
<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1175585">APZ wheel transactions test</a>
<p id="display"></p>
<div id="outer-frame">
    <div id="inner-frame">
        <div id="inner-content"></div>
    </div>
</div>
<pre id="test">
<script type="application/javascript">
async function scrollWheelOver(element, deltaY) {
  await promiseNativeWheelAndWaitForScrollEvent(element, 10, 10, 0, deltaY);
}
async function test() {
  var outer = document.getElementById("outer-frame");
  var inner = document.getElementById("inner-frame");
  // Register a wheel event listener that records the target of
  // the last wheel event, so that we can make assertions about it.
  let lastWheelTarget;
  let firstWheelTarget;
  let wheelEventOccurred = false;
  var wheelTargetRecorder = function(e) {
    if (!wheelEventOccurred) {
      firstWheelTarget = e.target;
      wheelEventOccurred = true;
    }
    lastWheelTarget = e.target;
  };
  window.addEventListener("wheel", wheelTargetRecorder);
  // Scroll |outer| to the bottom.
  while (outer.scrollTop < outer.scrollTopMax) {
    await scrollWheelOver(outer, -10);
  }
  is(lastWheelTarget, firstWheelTarget,
     "target " + lastWheelTarget.id + " should be " + lastWheelTarget.id);
  window.removeEventListener("wheel", wheelTargetRecorder);
  // Immediately after, scroll it back up a bit.
  await scrollWheelOver(outer, 10);
  // Check that it was |outer| that scrolled back, and |inner| didn't
  // scroll at all, as all the above scrolls should be in the same
  // transaction.
  ok(outer.scrollTop < outer.scrollTopMax, "'outer' should have scrolled back a bit");
  is(inner.scrollTop, 0, "'inner' should not have scrolled");
  // The next part of the test is related to the transaction timeout.
  // Turn it down a bit so waiting for the timeout to elapse doesn't
  // slow down the test harness too much.
  var timeout = 5;
  await SpecialPowers.pushPrefEnv({"set": [["mousewheel.transaction.timeout", timeout]]});
  SimpleTest.requestFlakyTimeout("we are testing code that measures actual elapsed time between two events");
  // Scroll up a bit more. It's still |outer| scrolling because
  // |inner| is still scrolled all the way to the top.
  await scrollWheelOver(outer, 10);
  // Wait for the transaction timeout to elapse.
  // timeout * 5 is used to make it less likely that the timeout is less than
  // the system timestamp resolution
  await SpecialPowers.promiseTimeout(timeout * 5);
  // Now scroll down. The transaction having timed out, the event
  // should pick up a new target, and that should be |inner|.
  await scrollWheelOver(outer, -10);
  ok(inner.scrollTop > 0, "'inner' should have been scrolled");
  // Finally, test scroll handoff after a timeout.
  // Continue scrolling |inner| down to the bottom.
  var prevScrollTop = inner.scrollTop;
  while (inner.scrollTop < inner.scrollTopMax) {
    await scrollWheelOver(outer, -10);
    // Avoid a failure getting us into an infinite loop.
    ok(inner.scrollTop > prevScrollTop, "scrolling down should increase scrollTop");
    prevScrollTop = inner.scrollTop;
  }
  // Wait for the transaction timeout to elapse.
  // timeout * 5 is used to make it less likely that the timeout is less than
  // the system timestamp resolution
  await SpecialPowers.promiseTimeout(timeout * 5);
  // Continued downward scrolling should scroll |outer| to the bottom.
  prevScrollTop = outer.scrollTop;
  while (outer.scrollTop < outer.scrollTopMax) {
    await scrollWheelOver(outer, -10);
    // Avoid a failure getting us into an infinite loop.
    ok(outer.scrollTop > prevScrollTop, "scrolling down should increase scrollTop");
    prevScrollTop = outer.scrollTop;
  }
}
SimpleTest.waitForExplicitFinish();
// Disable smooth scrolling because it makes the test flaky (we don't have a good
// way of detecting when the scrolling is finished).
// Also, on macOS, force the native events to be wheel inputs rather than pan
// inputs since this test is specifically testing things related to wheel
// transactions.
pushPrefs([["general.smoothScroll", false],
           ["apz.test.mac.synth_wheel_input", true],
           ["mousewheel.transaction.timeout", 1500],
           ["dom.event.wheel-event-groups.enabled", true]])
.then(waitUntilApzStable)
.then(test)
.then(SimpleTest.finish, SimpleTest.finishWithFailure);
</script>
</pre>
</body>
</html>