LayoutTests/editing/selection/mixed-editability-6.html

<p>This tests Select All when the caret is inside an editable region that is inside a non editable region.  Whenever the selection is in an editable region, Select All should select the contents of the highest editable root.</p>
<div contenteditable="true">
<div>One</div>
<div contenteditable="false"><span>Two</span> <span id="start" contenteditable="true">Three</span></div>
<div>Four</div>
</div>

<script>
var span = document.getElementById("start");
var sel = window.getSelection();
sel.setPosition(span, 0);

document.execCommand("SelectAll");
</script>