diff --git a/src/main.cc b/src/main.cc
index f8338c4..82b5c7d 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -21,10 +21,61 @@
  */
 
 #include "sqlite-helper.h"
+#include <iostream>
+
+using namespace std;
+using namespace boost;
+
+typedef boost::error_info<struct tag_errmsg, std::string> errmsg_info_str; 
+
 
 int
 main (int argc, char **argv)
 {
-  DbHelper db ("./");
+  try
+    {
+      DbHelper db ("./");
+
+      HashPtr hash = db.RememberStateInStateLog ();
+      // should be empty
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      //
+      db.UpdateDeviceSeqno ("Alex", 1);
+      hash = db.RememberStateInStateLog ();
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      db.UpdateDeviceSeqno ("Alex", 2);
+      hash = db.RememberStateInStateLog ();
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      db.UpdateDeviceSeqno ("Alex", 2);
+      hash = db.RememberStateInStateLog ();
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      db.UpdateDeviceSeqno ("Alex", 1);
+      hash = db.RememberStateInStateLog ();
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      db.FindStateDifferences ("00", "ec0a9941fa726e1fb8f34ecdbd8e3faa75dc9dba22e6a2ea1d8482aae5fdfb52");
+      db.FindStateDifferences ("ec0a9941fa726e1fb8f34ecdbd8e3faa75dc9dba22e6a2ea1d8482aae5fdfb52", "00");
+      db.FindStateDifferences ("869c38c6dffe8911ced320aecc6d9244904d13d3e8cd21081311f2129b4557ce",
+                               "ec0a9941fa726e1fb8f34ecdbd8e3faa75dc9dba22e6a2ea1d8482aae5fdfb52");
+      db.FindStateDifferences ("ec0a9941fa726e1fb8f34ecdbd8e3faa75dc9dba22e6a2ea1d8482aae5fdfb52",
+                               "869c38c6dffe8911ced320aecc6d9244904d13d3e8cd21081311f2129b4557ce");
+
+      db.UpdateDeviceSeqno ("Bob", 1);
+      hash = db.RememberStateInStateLog ();
+      cout << "Hash: [" << *hash << "]" << endl;
+
+      db.FindStateDifferences ("00", "48f4d95b503b9a79c2d5939fa67722b13fc01db861fc501d09efd0a38dbafab8");
+      db.FindStateDifferences ("ec0a9941fa726e1fb8f34ecdbd8e3faa75dc9dba22e6a2ea1d8482aae5fdfb52",
+                               "48f4d95b503b9a79c2d5939fa67722b13fc01db861fc501d09efd0a38dbafab8");
+    }
+  catch (const boost::exception &e)
+    {
+      cout << "ERRORR: " << *get_error_info<errmsg_info_str> (e) << endl;
+    }
+
   return 0;
 }