chromium/third_party/blink/web_tests/paint/overflow/fixed-background-on-scroller-scroll.html

<!DOCTYPE html>
<style>
::-webkit-scrollbar {
  display: none;
}
</style>
Tests painting of scrolled container with fixed background.
Passes if the background doesn't scroll.
<div id="container" style="width: 200px; height: 200px; overflow: scroll; background: linear-gradient(red, blue); background-attachment: fixed">
  <div style="height: 2000px"></div>
</div>
<script>
onload = function() {
  container.scrollTop = 1000;
};
</script>