chromium/third_party/blink/web_tests/fast/backgrounds/tiny-tile-zoomed.html

<!DOCTYPE html>
<style>

div {
  width: 100px;
  height: 100px;
  background-color: green;
  background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAABkCAYAAACsG+FjAAAAEUlEQVQoz2NgGAWjYBQMJAAAA4QAAUvQkjcAAAAASUVORK5CYII=');
  background-size: 1px 50px;
}

</style>

<div></div>

<script>
  if (window.testRunner)
    testRunner.zoomPageOut();
</script>