chromium/src/third_party/blink/web_tests/editing/selection/move-by-line-005.html

<script src="../../resources/ahem.js"></script>
<p>
    Test for <i><a href="rdar://problem/6967596">rdar://problem/6967596</a>
    Safari hung using 100% CPU when I tried to look up a word in
    Dictionary using command-control-d</i>.
</p>
<p id="result">FAIL: Test did not run</p>
<div id="target" style="font: 20px Ahem; width: 320px; -webkit-user-modify: read-write;">Text and text<!-- --> more <!-- -->text</div>
<script>
    if ("testRunner" in window)
        testRunner.dumpAsText();

    var target = document.getElementById("target");
    var selection = getSelection();

    selection.collapse(target.firstChild, 13);
    selection.modify("move", "backward", "line");

    var pass = (selection.anchorNode === target.firstChild && selection.anchorOffset === 0);

    document.getElementById("result").innerText = pass ? "PASS" : "FAIL";
</script>