encoding: remove duplicate buf() and get() methods from Buffer class

Change-Id: If885d4199d6c9df9b9b46664c3641c9a14a77eab
diff --git a/tests/unit-tests/security/transform/signer-filter.t.cpp b/tests/unit-tests/security/transform/signer-filter.t.cpp
index 450f9ff..5db93a7 100644
--- a/tests/unit-tests/security/transform/signer-filter.t.cpp
+++ b/tests/unit-tests/security/transform/signer-filter.t.cpp
@@ -90,7 +90,7 @@
   bufferSource(data, sizeof(data)) >> signerFilter(DigestAlgorithm::SHA256, sKey) >> streamSink(os2);
   auto sig = os2.buf();
 
-  BOOST_CHECK(verifySignature(data, sizeof(data), sig->buf(), sig->size(), pubKey->buf(), pubKey->size()));
+  BOOST_CHECK(verifySignature(data, sizeof(data), sig->data(), sig->size(), pubKey->data(), pubKey->size()));
 }
 
 BOOST_AUTO_TEST_CASE(Ecdsa)
@@ -127,7 +127,7 @@
   bufferSource(data, sizeof(data)) >> signerFilter(DigestAlgorithm::SHA256, sKey) >> streamSink(os2);
   auto sig = os2.buf();
 
-  BOOST_CHECK(verifySignature(data, sizeof(data), sig->buf(), sig->size(), pubKey->buf(), pubKey->size()));
+  BOOST_CHECK(verifySignature(data, sizeof(data), sig->data(), sig->size(), pubKey->data(), pubKey->size()));
 }
 
 BOOST_AUTO_TEST_CASE(InvalidKey)