chromium/third_party/blink/web_tests/external/wpt/css/css-scroll-snap/snap-after-relayout/focus-element-no-snap.html

<!doctype html>
<title>Resnap to focused element after relayout</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>

#snapper {
    width: 100px;
    height: 200px;
    overflow-x: scroll;
    scroll-snap-type: x mandatory;
    color: white;
    background-color: oldlace;
    display: flex;
    align-items: center;
}
.child {
    margin-right: 0.5rem;
    height: 90%;
    scroll-snap-align: start;
    padding: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    width: 100px;
    height: 100px;
    background-color: indigo;
}
</style>

<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#re-snap">

<div id=snapper>
    <div class="child no-snap" tabindex=-1></div>
    <div class=child></div>
    <div class="child" id ="focus" tabindex=-1></div>
    <div class="child" tabindex=-1></div>
    <div class=child></div>
    <div class=child></div>
</div>

<script>

test(t => {
    document.getElementById("focus").focus();
    const element = document.getElementById("snapper");
    element.style.width = "101px";
    assert_equals(element.scrollLeft, 0);
});
</script>