chromium/third_party/blink/web_tests/paint/invalidation/background/background-attachment-fixed-scrolled.html

<!DOCTYPE html>
<style>
#bloat {
    height: 1000px;
}

#composited-background-attachment-fixed {
    position: absolute;
    left: 50px;
    top: 200px;
    width: 500px;
    height: 1000px;
    background: url('../resources/grid.png') fixed;
    will-change: opacity;
}
</style>
<div id="bloat">
The test verifies background-attachment:fixed gets invalidated after scroll even if they are composited.
</div>
<div id="composited-background-attachment-fixed"></div>
<script src="../resources/text-based-repaint.js"></script>
<script>
onload = runRepaintAndPixelTest;
function repaintTest() {
  scrollTo(0, 123);
}
</script>