sync: improved unit tests

refs: #4264

Change-Id: I981f3d8f653e4750ee6f9d77f2c89188f11d8ebb
diff --git a/src/lsdb.cpp b/src/lsdb.cpp
index 4de69ef..789edf6 100644
--- a/src/lsdb.cpp
+++ b/src/lsdb.cpp
@@ -68,23 +68,8 @@
   , m_sync(m_nlsr.getNlsrFace(),
            [this] (const ndn::Name& routerName, const std::string& lsaType,
                    const uint64_t& sequenceNumber) {
-             ndn::Name lsaKey = routerName;
-             lsaKey.append(lsaType);
-
-             if (lsaType == NameLsa::TYPE_STRING) {
-                 return isNameLsaNew(lsaKey, sequenceNumber);
-             }
-             else if (lsaType == AdjLsa::TYPE_STRING) {
-                 return isAdjLsaNew(lsaKey, sequenceNumber);
-             }
-             else if (lsaType == CoordinateLsa::TYPE_STRING) {
-                 return isCoordinateLsaNew(lsaKey, sequenceNumber);
-             }
-             else {
-               return false;
-             }
-           },
-           m_nlsr.getConfParameter())
+             return isLsaNew(routerName, lsaType, sequenceNumber);
+           }, m_nlsr.getConfParameter())
   , m_lsaRefreshTime(0)
   , m_adjLsaBuildInterval(ADJ_LSA_BUILD_INTERVAL_DEFAULT)
   , m_sequencingManager()
@@ -1313,4 +1298,24 @@
   return false;
 }
 
+bool
+Lsdb::isLsaNew(const ndn::Name& routerName, const std::string& lsaType,
+               const uint64_t& sequenceNumber) {
+  ndn::Name lsaKey = routerName;
+  lsaKey.append(lsaType);
+
+  if (lsaType == NameLsa::TYPE_STRING) {
+    return isNameLsaNew(lsaKey, sequenceNumber);
+  }
+  else if (lsaType == AdjLsa::TYPE_STRING) {
+    return isAdjLsaNew(lsaKey, sequenceNumber);
+  }
+  else if (lsaType == CoordinateLsa::TYPE_STRING) {
+    return isCoordinateLsaNew(lsaKey, sequenceNumber);
+  }
+  else {
+    return false;
+  }
+}
+
 } // namespace nlsr