chromium/third_party/blink/web_tests/fast/forms/color/color-picker-appearance-manual-color-change.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='#EA5FB0'>

<script>
  window.onload = openPickerAppearanceOnly(document.querySelector('input'),() => {
    internals.pagePopupWindow.focus();
    const popupDocument = internals.pagePopupWindow.document;
    const formatToggler = popupDocument.querySelector('format-toggler');
    formatToggler.click();
    const hValueContainer = popupDocument.getElementById('hValueContainer');
    const hValueContainerRect = hValueContainer.getBoundingClientRect();
    eventSender.mouseMoveTo(hValueContainerRect.right - 1, hValueContainerRect.top);
    eventSender.mouseDown();
    eventSender.mouseUp();
    eventSender.keyDown('Backspace');
    eventSender.keyDown('Backspace');
    eventSender.keyDown('Backspace');
    eventSender.keyDown('2');
    eventSender.keyDown('7');
    eventSender.keyDown('6');
  });
</script>