snav-navigate-visible-elements-in-visual-viewport-only.html

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="resources/snav-testharness.js"></script>

<style>
  div {
    width: 100px;
    height: 100px;
    background-color: green;
    position: absolute;
  }

  #blocker {
    top: 480px;
    height: 50px;
    background-color: yellow;
  }

  #A {
    top: 490px;
  }
</style>

<div id="start" tabindex="0"></div>
<div id="A" tabindex="0"></div>
<div id="blocker"></div>

<script>
  const A = document.getElementById("A");
  const start = document.getElementById("start");

  snav.assertSnavEnabledAndTestable();
  start.focus();

  test(() => {
    window.internals.setPageScaleFactor(1.2);

    // Down should scroll the visual viewport, since there's no targets
    // availabe on screen(Visible part of element 'A' is obscured by
    // blocker element).
    snav.triggerMove('Down');
    assert_equals(document.activeElement,
                  start,
                  "Focus should not be moved.");
    snav.triggerMove('Up');

    window.internals.setPageScaleFactor(1);
    // Now we can see visible part of element 'A'.
    snav.triggerMove('Down');
    assert_equals(document.activeElement,
                  A,
                  "Focus should be moved to A.");
  }, "Don't navigate to elements that are off screen.");
</script>

chromium/third_party/blink/web_tests/fast/spatial-navigation/snav-navigate-visible-elements-in-visual-viewport-only.html