LayoutTests/editing/selection/extend-by-sentence-002.html

<div id="target">All of this should be selected</div><div>None of this should be selected.</div>
<p id="result"></p>
<script>
    if (window.testRunner)
        testRunner.dumpAsText();

    var target = document.getElementById("target");
    var result = document.getElementById("result");
    var sel = getSelection();
    sel.setBaseAndExtent(target, 0, target, 1);
    sel.modify("extend", "forward", "sentence");
    var selectedText = sel.toString().trim();

    if (selectedText == "All of this should be selected") {
        result.innerText = "PASS";
    } else {
        result.innerText = "FAIL: Selected range is '" + selectedText + "'";
    }
</script>