chromium/third_party/blink/web_tests/fast/forms/select-popup/popup-menu-accessibility-minimum-target-size.html

<!DOCTYPE html>
<title>Test the minimum size of the option element within the select dropdown</title>
<link rel=help href="https://www.w3.org/WAI/WCAG22/Understanding/target-size-minimum.html">
<link rel=help href="https://github.com/openui/open-ui/issues/1026">
<script src="../resources/picker-common.js"></script>
<script src="../../../resources/testdriver.js"></script>
<script src="../../../resources/testdriver-vendor.js"></script>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>

<select>
  <option>A</option>
</select>

<script>
function test(dimension, expectedValue, message) {
  promise_test(() => {
    const menu = document.querySelector("select");
    return openPicker(menu)
    .then(() => {
      let optionRect = internals.pagePopupWindow.global.picker.selectElement_.options[0].getBoundingClientRect();
      assert_greater_than_equal(optionRect[dimension], expectedValue, message);
    });
  }, message);
}

test("height", 24, "The minimum height of the option element in the popup menu should be 24 CSS pixels.");
test("width", 24, "The minimum width of the option element in the popup menu should be 24 CSS pixels.");
</script>