chromium/third_party/blink/manual_tests/select-popup-tooltip-test.html

<!DOCTYPE html>
<html>
<body>
<h3> Test tool tip is correctly shown when popup select is displayed.</h3>
<ol>
<li>Click the following select tag.</li>
<li> Move mouse cursor on "option 1" and stop moving.</li>
<li> After seconds, make sure you can see tool tip text "This is the first option".</li>
<li> Move mouse cursor on "option 2" and stop moving.</li>
<li> Make sure you can see tool tip text "This is the second option".</li>
</ol>

<select size=1>
<option title="This is the first option">option 1</option>
<option title="This is the second option">option 2</option>
<option title="This is the third option">option 3</option>
</select>
</body>
</html>