chromium/third_party/blink/web_tests/fast/forms/number/number-appearance-vertical.html

<!DOCTYPE html>
<meta name=fuzzy content="maxDifference=0-3; totalPixels=0-100">
<style>
div {
  display: inline-block;
  height: 23ch;
  line-height: 1.6;
}
</style>
<html>
<body>
<div style="writing-mode: vertical-rl;">
vertical-rl
<input type="number" value=1 style="direction: ltr;">
<input type="number" value=2 dir="ltr">
<input type="number" value=3 style="direction: rtl;">
<input type="number" value=4 dir="rtl">
</div>

<div style="writing-mode: vertical-lr;">
vertical-lr
<input type="number" value=5 style="direction: ltr;">
<input type="number" value=6 dir="ltr">
<input id="i7" type="number" value=7 style="direction: rtl;">
<input type="number" value=8 dir="rtl">
</div>

<br>

<div style="writing-mode: sideways-rl;">
sideways-rl
<input type="number" value=9 style="direction: ltr;">
<input type="number" value=10 dir="ltr">
<input type="number" value=11 style="direction: rtl;">
<input type="number" value=12 dir="rtl">
</div>

<div style="writing-mode: sideways-lr;">
sideways-lr
<input type="number" value=13 style="direction: ltr;">
<input type="number" value=14 dir="ltr">
<input type="number" value=15 style="direction: rtl;">
<input type="number" value=16 dir="rtl">
</div>

<script>
if (window.internals) {
  for (let input of document.querySelectorAll('input')) {
    internals.setPseudoClassState(input, ':hover', true);
  }
} else {
  var input = document.getElementById('i7');
  // A spinbutton should be showing on the top (left)
  input.focus();
}
</script>
</body>
</html>