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

Change-Id: Ic1c8d6925557ea5da2011ab68f16587eef2102f3
Refs: #3153
diff --git a/tests/unit-tests/security/v2/key-chain.t.cpp b/tests/unit-tests/security/v2/key-chain.t.cpp
index ddc020b..db14070 100644
--- a/tests/unit-tests/security/v2/key-chain.t.cpp
+++ b/tests/unit-tests/security/v2/key-chain.t.cpp
@@ -300,11 +300,18 @@
     SigningInfo(SigningInfo::SIGNER_TYPE_ID, id.getName()),
     signingByIdentity(id.getName()),
 
+    SigningInfo(id),
+    signingByIdentity(id),
+
     SigningInfo(SigningInfo::SIGNER_TYPE_KEY, key.getName()),
     signingByKey(key.getName()),
 
+    SigningInfo(key),
+    signingByKey(key),
+
     SigningInfo(SigningInfo::SIGNER_TYPE_CERT, cert.getName()),
     signingByCertificate(cert.getName()),
+    signingByCertificate(cert),
 
     SigningInfo(SigningInfo::SIGNER_TYPE_SHA256),
     signingWithSha256()