mustella/tests/PerModuleStyles/SWFs/assets/SparkAlphaMain.mxml

<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark"
    width="300" height="250" >
    <s:layout>
        <s:VerticalLayout />
    </s:layout>
    <s:Button id="buttonId" label="Test1"/>
</s:Application>