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<!DOCTYPE HTML>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, minimum-scale=1.0">
<title>Tests scroll anchoring updates in-progress wheel scrolling __relatively__</title>
<script src="apz_test_utils.js"></script>
<script src="apz_test_native_event_utils.js"></script>
<script src="/tests/SimpleTest/paint_listener.js"></script>
<style>
body { margin: 0 }
#target > div {
height: 500px;
}
</style>
<div id="target"></div>
<div class="spacer" style="height: 1000vh"></div>
<script>
const targetElement = document.getElementById("target");
async function test() {
// Fistly send a wheel event to measure the scroll amount of one event.
let transformEndPromise = promiseTransformEnd();
await synthesizeNativeWheel(window, 50, 50, 0, -50);
await transformEndPromise;
ok(window.scrollY > 0, "Should be scrolled to some amount");
const firstScrollAmount = window.scrollY;
// Now send a wheel event again.
transformEndPromise = promiseTransformEnd();
await synthesizeNativeWheel(window, 50, 50, 0, -50);
await promiseApzFlushedRepaints();
// And insert an element during the wheel scrolling is still in progress.
targetElement.appendChild(document.createElement("div"));
await transformEndPromise;
// Give scroll offsets a chance to sync.
await promiseApzFlushedRepaints();
// Though in an ideal environment, the expected total scroll amount should
// be `firstScrollAmount * 2 + 500`, we don't expect it on our CIs, so we
// assume here;
// 1) it's greater than double of the first scroll amount since it should
// include the height of the inserted element.
// 2) it's greater than the first scroll amount + the height of the inserted
// element.
ok(window.scrollY > firstScrollAmount * 2,
`the scroll amount ${window.scrollY} should be greater than double of the first scroll amount ${firstScrollAmount*2}`);
ok(window.scrollY > firstScrollAmount + 500,
`the scroll amount ${window.scrollY} should also be greater than the first scroll amount + the inserted element height ${firstScrollAmount+500}`);
}
waitUntilApzStable()
.then(test)
.then(subtestDone, subtestFailed);
</script>