diff --git a/ccnx/sync-app-socket.h b/ccnx/sync-app-socket.h
index 07c0aa0..bb533a9 100644
--- a/ccnx/sync-app-socket.h
+++ b/ccnx/sync-app-socket.h
@@ -82,7 +82,7 @@
   void fetchString(const std::string &prefix, const SeqNo &seq, CcnxWrapper::StringDataCallback callback, int retry = 0);
   void fetchRaw(const std::string &prefix, const SeqNo &seq, CcnxWrapper::RawDataCallback callback, int retry = 0);
 
-  void passCallback(std::vector<MissingDataInfo> &v) {m_newDataCallback(v, this);}
+  void passCallback(const std::vector<MissingDataInfo> &v) {m_newDataCallback(v, this);}
 
 private:
   uint32_t
diff --git a/test/test_app_socket.cc b/test/test_app_socket.cc
index 8a3f864..6a6e04a 100644
--- a/test/test_app_socket.cc
+++ b/test/test_app_socket.cc
@@ -49,11 +49,11 @@
     // cout << str1 << ", " << str2 << endl;
   }
 
-  void fetchAll(vector<MissingDataInfo> &v, SyncAppSocket *socket) {
+  void fetchAll(const vector<MissingDataInfo> &v, SyncAppSocket *socket) {
     int n = v.size();
     for (int i = 0; i < n; i++) {
-      SeqNo s = ++v[i].low;
-      for(; s <= v[i].high; ++s) {
+      SeqNo s = v[i].low;
+      for(++s; s <= v[i].high; ++s) {
         socket->fetchString(v[i].prefix, s, bind(&TestSocketApp::set, this, _1, _2));
       }
     }
diff --git a/test/test_sync_logic.cc b/test/test_sync_logic.cc
index 0d77cd0..2cfde28 100644
--- a/test/test_sync_logic.cc
+++ b/test/test_sync_logic.cc
@@ -44,7 +44,7 @@
   {
   }
 
-  void wrapper (vector<MissingDataInfo> &v) {
+  void wrapper (const vector<MissingDataInfo> &v) {
     int n = v.size();
     for (int i = 0; i < n; i++) {
       onUpdate (v[i].prefix, v[i].high, v[i].low);
diff --git a/wscript b/wscript
index 0bcb242..8c52b8b 100644
--- a/wscript
+++ b/wscript
@@ -8,6 +8,7 @@
     opt.add_option('--log4cxx', action='store_true',default=False,dest='log4cxx',help='''Compile with log4cxx/native NS3 logging support''')
     opt.add_option('--ns3',     action='store_true',default=False,dest='ns3_enable',help='''Compile as NS-3 module''')
     opt.add_option('--ns3-debug', action='store_true',default=False,dest='ns3_debug',help='''Link against debug NS3 libraries. Optimized version will be used otherwise''')
+    opt.add_option('--test', action='store_true',default=False,dest='_test',help='''build unit tests''')
     opt.load('compiler_c')
     opt.load('compiler_cxx')
     opt.load('boost')
@@ -53,6 +54,9 @@
     else:
         conf.env.append_value('CXXFLAGS', ['-O3'])
 
+    if conf.options._test:
+      conf.define('_TEST', 1)
+
     try:
         conf.load('doxygen')
     except:
@@ -145,13 +149,14 @@
             )
         
         # Unit tests
-        unittests = bld.program (
-            target="unit-tests",
-            source = bld.path.ant_glob(['test/**/*.cc']),
-            features=['cxx', 'cxxprogram'],
-            use = 'BOOST_TEST sync',
-            includes = ['model', 'ccnx', 'helper'],
-            )
+        if bld.get_define("_TEST"):
+          unittests = bld.program (
+              target="unit-tests",
+              source = bld.path.ant_glob(['test/**/*.cc']),
+              features=['cxx', 'cxxprogram'],
+              use = 'BOOST_TEST sync',
+              includes = ['model', 'ccnx', 'helper'],
+              )
 
         if bld.get_define ("HAVE_LOG4CXX"):
             libsync.use += ' LOG4CXX'