snav-dont-search-focused-offscreen-scroller.html

<!doctype html>
<div id="start" tabindex="0" style="overflow-y: scroll; height: 35px; margin-top: 100%">
  <br><br><br>
  <p>Text</p>
</div>

<p>Don't search inside or scroll the focused scrollable element when it is offscreen.</p>

<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="resources/snav-testharness.js"></script>
<script>
  var resultMap = [
    ["Down", "start"],  // Scroll performed at Window
  ];

  let start = document.getElementById("start");

  function postFocusMoveCheck() {
    assert_equals(start.scrollTop, 0, "Offscreen scroller shouldn't be scrolled.");
  }

  start.focus({preventScroll:true});

  test(function() {
    assert_equals(window.scrollY, 0);
  }, "Window shouldn't be scrolled by focus.")

  snav.assertFocusMoves(resultMap, true, postFocusMoveCheck);
</script>

chromium/third_party/blink/web_tests/fast/spatial-navigation/snav-dont-search-focused-offscreen-scroller.html