chromium/third_party/blink/web_tests/external/wpt/css/css-scroll-snap/scroll-snap-stop-002-nested.tentative.html

<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#scroll-snap-stop" />
<link rel="help" href="https://drafts.csswg.org/css-scroll-snap-1/#snap-overflow" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
div {
  position: absolute;
}
.scroller {
  width: 400px;
  height: 100px;
  overflow: scroll;
  scroll-snap-type: x mandatory;
}
#space {
  left: 0px;
  top: 0px;
  width: 2100px;
  height: 50px;
}
.target {
  width: 50px;
  height: 50px;
  scroll-snap-align: start;
  top: 0px;
}
</style>

<div class="scroller" id="scroller7">
  <div id="space"></div>
  <div class="target" style="left:   0px;"></div>
  <div class="target" style="left: 400px; width: 900px;"></div>
  <div class="target" style="left: 900px; scroll-snap-stop: always;"></div
</div>

<script>

test(() => {
  assert_equals(scroller7.scrollLeft, 0);
  assert_equals(scroller7.scrollTop, 0);

  // start                                       dest  always
  //   |-------------------------|================|=====|=====
  //   0                        400              700   900

  // Scoll on the element whose snap area is larger than the snapport.
  scroller7.scrollBy(600, 0);
  // Stops before the smaller snap area @ 900px enters the snapport.
  assert_equals(scroller7.scrollLeft + scroller7.clientWidth, 900);
  assert_equals(scroller7.scrollTop, 0);

  scroller7.scrollTo(0, 0);
  scroller7.scrollBy(800, 0);
  // Now the smaller snap area is closer, so we snap to it.
  assert_equals(scroller7.scrollLeft, 900);
  assert_equals(scroller7.scrollTop, 0);
}, "`scroll-snap-stop: always` snap point is further than the scroll " +
   "destination and a snap area covers the snapport");

</script>