LayoutTests/fast/text/remove-zero-length-run.html

<div style="position: absolute; top: 40px; left: 40px; width: 140px; font-family: ahem; font-size: 20px; direction: rtl;">12345 abcde</div>
<div id="result">FAIL: Test did not run</div>
<script>
    if (window.layoutTestController)
        layoutTestController.dumpAsText();

    var offset = document.caretRangeFromPoint(125, 50).startOffset;
    document.getElementById("result").innerText = offset === 2 ? "PASS" : "FAIL: Hit offset " + offset;
</script>