XmlPullParserException when testing using Simple-Xml and Robolectric

I'm currently using Robolectric to write tests for Android. However when I try to unmarshall an XML document using simple-xml it throws

No valid parser classes found in      
org.kxml2.io.kXmlParser,org.kxml2.io.KXmlSerializer

After further inspection it looks like the exception occurs inside the PullProvider in the simple-xml framework at

XmlPullParser parser = factory.newPullParser();

It looks like Robolectric doesn't support XmlPullParser. Has anyone found a workaround to this?