add assertions to verify Id generation in signature object test

Author: shunkica

test/signature-object-tests.spec.ts

@@ -389,7 +389,18 @@ describe("Valid signatures with ds:Object elements", function () {
       ],
     });
 
-    sig.computeSignature(xml);
+    sig.computeSignature(xml, { prefix: "ds" });
+    const signedXml = sig.getSignedXml();
+    const doc = new xmldom.DOMParser().parseFromString(signedXml);
+
+    // Verify that Data element got an Id
+    const dataEl = select1Ns("/root/ds:Signature/ds:Object/Data[@Id]", doc);
+    isDomNode.assertIsElementNode(dataEl);
+
+    // Verify Reference URI points to the generated Id
+    const refEl = select1Ns("/root/ds:Signature/ds:SignedInfo/ds:Reference", doc);
+    isDomNode.assertIsElementNode(refEl);
+    expect(refEl.getAttribute("URI")).to.match(/^#_\d+$/);
   });
 });