QName xmlType = Constants.TYPE_LITERAL_QNAME;
QName value = new QName("http://some-ns", "localPart", "ns1");
AbstractSerializerFactory serializerFactory = (AbstractSerializerFactory)typeMapping.getSerializer(QName.class, xmlType);
SerializerSupport ser = (SerializerSupport)serializerFactory.getSerializer();
Result result = ser.serialize(xmlName, xmlType, value, serContext, null);
assertNotNull(result);
// serialization registers the prefix
NamespaceRegistry nsRegistry = serContext.getNamespaceRegistry();
assertEquals("ns1", nsRegistry.getPrefix("http://some-ns"));