percentage-keyboard-scroll-minimum-distance.html

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../../resources/run-after-layout-and-paint.js"></script>
<div id="scroller" tabindex=1 style="width: 5px; height: 5px; overflow: scroll;">
  <div style="width: 1000px; height:1000px;"></div>
</div>
<script>
  "use strict";

  function runTest() {
    if (window.eventSender && window.internals) {
      internals.settings.setScrollAnimatorEnabled(false);
      internals.settings.setHideScrollbars(true);

      test(() => {
        const scroller = document.getElementById("scroller");

        scroller.focus();
        assert_equals(document.activeElement.id, "scroller");
        eventSender.keyDown("ArrowDown");
        eventSender.keyDown("ArrowRight");

        assert_greater_than(scroller.scrollTop, 0);
        assert_greater_than(scroller.scrollLeft, 0);
      }, "Ensure percent-based keyboard scroll can always scroll, even on small scrollers.");
    }
  }
  addEventListener('load', runTest);
</script>

chromium/third_party/blink/web_tests/fast/scrolling/percentage-keyboard-scroll-minimum-distance.html