security: Allow Identity and Key abstractions to be used in SigningInfo

Change-Id: Ic1c8d6925557ea5da2011ab68f16587eef2102f3
Refs: #3153
diff --git a/tests/unit-tests/security/signing-info.t.cpp b/tests/unit-tests/security/signing-info.t.cpp
index 5b63ae7..cfada95 100644
--- a/tests/unit-tests/security/signing-info.t.cpp
+++ b/tests/unit-tests/security/signing-info.t.cpp
@@ -158,6 +158,8 @@
     .setSigningIdentity("/identity")
     .setSigningKeyName("/key/name")
     .setSigningCertName("/cert/name")
+    .setPibIdentity(Identity())
+    .setPibKey(Key())
     .setSha256Signing()
     .setDigestAlgorithm(DigestAlgorithm::SHA256)
     .setSignatureInfo(SignatureInfo());