chromium/third_party/blink/web_tests/fast/forms/color/color-picker-appearance-color-well-down-keyboard-navigation-from-top-left-corner.html

<!DOCTYPE html>
<meta name=fuzzy content="maxDifference=0-3; totalPixels=0-1000">
<script src="../../../resources/testdriver.js"></script>
<script src="../../../resources/testdriver-vendor.js"></script>
<script src="../resources/picker-common.js"></script>

<input type='color' value='#A8A8A8'>

<script>
  window.onload = openPickerAppearanceOnly(document.querySelector('input'),() => {
    internals.pagePopupWindow.focus();
    const popupDocument = internals.pagePopupWindow.document;
    const colorWell = popupDocument.querySelector('color-well');
    const colorWellRect = colorWell.getBoundingClientRect();
    eventSender.mouseMoveTo(colorWellRect.left, colorWellRect.top);
    eventSender.mouseDown();
    eventSender.mouseUp();
    for (let i = 0; i < 25; i++) {
      eventSender.keyDown('ArrowDown');
    }
  });
</script>