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chromium/third_party/blink/web_tests/fast/forms/select-popup/select-many-options-hang.html 

<!DOCTYPE html>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script src="../../../resources/testdriver.js"></script>
<script src="../../../resources/testdriver-vendor.js"></script>
<script src="../resources/picker-common.js"></script>
<body>
<script>
const select = document.createElement('select');
for (let i = 0; i < 10000; i++) {
  const option = document.createElement('option');
  option.textContent = i;
  select.appendChild(option);
}
document.body.appendChild(select);

// This test passes if it doesn't hang or time out.

promise_test(async () => {
  assert_equals(select.value, '0', 'Initial select.value.');
  await openPicker(select);
  eventSender.keyDown('ArrowDown');
  eventSender.keyDown('Enter');
  assert_equals(select.value, '1', 'select.value after ArrowDown.');
}, 'Selects with 10000+ options should be usable.');
</script>