LayoutTests/editing/undo/undo-misspellings.html

<script>
if (window.testRunner)
     testRunner.dumpEditingCallbacks();
</script>
<div id="test" contenteditable="true"></div>

<script>
var s = window.getSelection();
s.setPosition(document.getElementById("test"), 0);

document.execCommand("InsertText", false, "sugare");
document.execCommand("InsertText", false, " ");
document.execCommand("InsertText", false, "sugari");
document.execCommand("InsertText", false, " ");
document.execCommand("InsertText", false, "sugarm");
document.execCommand("InsertText", false, " ");
document.execCommand("Undo");
</script>