use namespace for ca and rename CaState to ca::RequestState

Change-Id: I2250bf7fb68503465dae18e16dc3c512fe809037
diff --git a/tests/unit-tests/challenge-credential.t.cpp b/tests/unit-tests/challenge-credential.t.cpp
index 00333ab..e048e29 100644
--- a/tests/unit-tests/challenge-credential.t.cpp
+++ b/tests/unit-tests/challenge-credential.t.cpp
@@ -54,7 +54,7 @@
   auto keyA = identityA.getDefaultKey();
   auto certA = key.getDefaultCertificate();
   RequestID requestId = {1,2,3,4,5,6,7,8};
-  CaState state(Name("/example"), requestId, RequestType::NEW, Status::BEFORE_CHALLENGE, certA, makeEmptyBlock(ndn::tlv::ContentType_Key));
+  ca::RequestState state(Name("/example"), requestId, RequestType::NEW, Status::BEFORE_CHALLENGE, certA, makeEmptyBlock(ndn::tlv::ContentType_Key));
 
   // create requester's credential
   auto identityB = addIdentity(Name("/trust/cert"));