third_party/WebKit/LayoutTests/editing/style/fontsize-1.html

<script src="../../resources/dump-as-markup.js"></script>
<div id="div" contenteditable="true"></div>
<ul id="console"></ul>

<script>

Markup.description("This test execCommand('FontSize', ...).  You should see 'small' 'medium' and 'large' below in every increasing font sizes.")

function log(str) {
    var li = document.createElement("li");
    li.appendChild(document.createTextNode(str));
    var console = document.getElementById("console");
    console.appendChild(li);
}

var div = document.getElementById("div");
var sel = window.getSelection();

sel.collapse(div, 0);
Markup.dump(div, 'initial');

if (document.execCommand("FontSize", false, "pasd"))
    log("Failure: execCommand('FontSize', [Illegal value]) should fail.");

if (!document.execCommand("FontSize", false, "2"))
    log("Failure: execCommand('FontSize', [Legal value]) failed.");
Markup.dump(div, 'fontsize 2');

document.execCommand("InsertText", false, "small");    
Markup.dump(div, 'type small');

if (!document.execCommand("FontSize", false, "4"))
    log("Failure: execCommand('FontSize', [Legal value]) failed.");
Markup.dump(div, 'fontsize 4');

document.execCommand("InsertText", false, "medium");
Markup.dump(div, 'type medium');

if (!document.execCommand("FontSize", false, "6"))
    log("Failure: execCommand('FontSize', [Legal value]) failed.");
Markup.dump(div, 'fontsize 6');

document.execCommand("InsertText", false, "large");
Markup.dump(div, 'type large');

Markup.dump('console', 'console');

</script>