chromium/third_party/blink/web_tests/fast/spatial-navigation/snav-applies-hover-mousemove.html

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

<style>
  div {
    width: 100px;
    height: 100px;
    margin: 5px;
    border: 1px solid black;
  }
  div:hover {
    background-color: dodgerblue;
  }
  iframe {
    width: 200px;
    height: 200px;
  }
</style>

<div id="first" tabindex="0">First</div>
<iframe srcdoc="
    <!DOCTYPE html>
    <style>
      div:hover {
        background-color: dodgerblue;
      }
      div {
        width: 100px;
        height: 100px;
        margin: 5px;
        border: 1px solid black;
      }
    </style>
    <div id='second' tabindex='0'>Second</div>"></iframe>
<div id="third" tabindex="0">Third</div>

<script>
  window.onload = async () => {
    // This test checks whether hover state is correctly applied and removed from
    // elements as the become and lose interest but includes a mouse move to
    // ensure it doesn't interfere with hover transitions.
    const iframe = document.querySelector("iframe");
    const first = document.getElementById("first");
    const second = iframe.contentDocument.getElementById("second");
    const third = document.getElementById("third");

    promise_test(async () => {
      snav.assertSnavEnabledAndTestable();

      // Move interest to |second|.
      snav.triggerMove("Down"); // |first|
      snav.triggerMove("Down"); // |iframe|
      snav.triggerMove("Down"); // |second|

      assert_equals(iframe.contentDocument.activeElement,
                    second, "|second| element gets interest.");
      assert_true(second.matches(":hover"),
                  "|second| should be hovered when interested.");
      assert_true(iframe.matches(":hover"),
                  "|iframe| should be hovered as element inside is hovered.");

      // Arbitrary mouse move on the main frame. This will un-hover the iframe,
      // ensure further spatial navigations remove and replace hover correctly.
      await mouseMoveTo(300, 300);
      assert_false(iframe.matches(":hover"),
                  "Mouse move should unhover |iframe|.");

      // Down again to interest |third|.
      snav.triggerMove("Down");
      assert_equals(document.activeElement,
                    third, "|third| element gets interest.");
      assert_true(third.matches(":hover"),
                  "|third| should be hovered when interested.");
      assert_false(second.matches(":hover"),
                  "|second| should no longer be hovered.");
      assert_false(iframe.matches(":hover"),
                  "|iframe| should no longer be hovered.");

    }, "Test hover application with mouse moves during spatial navigation.");
  }
</script>