Adding a unit test using boost Unit Test Framework
diff --git a/model/sync-seq-no.h b/model/sync-seq-no.h
index fb9e6b8..a6005af 100644
--- a/model/sync-seq-no.h
+++ b/model/sync-seq-no.h
@@ -55,7 +55,7 @@
     , m_seq (seq)
   { }
 
-  inline Digest
+  inline const Digest&
   getDigest () const;
 
   /**
@@ -124,11 +124,10 @@
   m_digest << m_session << m_seq;
 }
   
-Digest
+const Digest&
 SeqNo::getDigest () const
 {
-  Digest digest;
-  return digest;
+  return m_digest;
 }