SignedInfo signedInfo = xmlSignature.getSignedInfo();
assertTrue(signedInfo.getLength() > 0);
for (int i = 0; i < signedInfo.getLength(); i++) {
Reference reference = signedInfo.item(i);
assertNotNull(reference);
ReferenceData referenceData = reference.getReferenceData();
assertNotNull(referenceData);
if (referenceData instanceof ReferenceNodeSetData) {
Iterator<Node> iter = ((ReferenceNodeSetData)referenceData).iterator();
assertTrue(iter.hasNext());