private void addDefaultTestFunctions() {
Iterator<TestFunction> testFunctions = testLoader.iterator();
while(testFunctions.hasNext()){
try {
TestFunction testFunction = testFunctions.next();
log.info("registering LDPath test function: {}",
testFunction.getSignature());
addTestFunction(testFunction);
} catch (ServiceConfigurationError e) {
log.warn("Unable to load function because of an "
+ e.getClass().getSimpleName(), e);
}