Assert.assertTrue(Extension.class.isAssignableFrom(clazz));
Extension extension = (Extension) clazz.newInstance();
//Initialize the parsers for the legacy subsystem (copied from the @Before method)
XMLMapper xmlMapper = XMLMapper.Factory.create();
ModelTestParser testParser = new TestParser(mainSubsystemName, extensionParsingRegistry);
ExtensionRegistry extensionParsingRegistry = new ExtensionRegistry(additionalInit.getProcessType(), new RunningModeControl(additionalInit.getExtensionRegistryRunningMode()));
xmlMapper.registerRootElement(new QName(TEST_NAMESPACE, "test"), testParser);
extension.initializeParsers(extensionParsingRegistry.getExtensionParsingContext("Test", xmlMapper));
//TODO extra parsers from additionalInit