diff --git a/tests/unit-tests/test-logic.cpp b/tests/unit-tests/test-logic.cpp
index 8459158..d883fe7 100644
--- a/tests/unit-tests/test-logic.cpp
+++ b/tests/unit-tests/test-logic.cpp
@@ -432,12 +432,12 @@
   {
     unsetenv("CHRONOSYNC_MAX_PACKET_SIZE");
     if (oldSize) {
-      setenv("CHRONOSYNC_MAX_PACKET_SIZE", oldSize->c_str(), 1);
+      setenv("CHRONOSYNC_MAX_PACKET_SIZE", oldSize->data(), 1);
     }
   }
 
 private:
-  ndn::optional<std::string> oldSize;
+  std::optional<std::string> oldSize;
 };
 
 BOOST_FIXTURE_TEST_CASE(MaxPacketCustomization, MaxPacketCustomizationFixture)
@@ -447,7 +447,7 @@
   setenv("CHRONOSYNC_MAX_PACKET_SIZE", "1500", 1);
   BOOST_CHECK_EQUAL(getMaxPacketLimit(), 1500);
 
-  setenv("CHRONOSYNC_MAX_PACKET_SIZE", ndn::to_string(ndn::MAX_NDN_PACKET_SIZE * 100).c_str(), 1);
+  setenv("CHRONOSYNC_MAX_PACKET_SIZE", std::to_string(ndn::MAX_NDN_PACKET_SIZE * 100).data(), 1);
   BOOST_CHECK_EQUAL(getMaxPacketLimit(), ndn::MAX_NDN_PACKET_SIZE);
 
   setenv("CHRONOSYNC_MAX_PACKET_SIZE", "1", 1);
diff --git a/tests/unit-tests/test-multiple-user.cpp b/tests/unit-tests/test-multiple-user.cpp
index db8ffcf..b8a5dbd 100644
--- a/tests/unit-tests/test-multiple-user.cpp
+++ b/tests/unit-tests/test-multiple-user.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
 /*
- * Copyright (c) 2012-2019 University of California, Los Angeles
+ * Copyright (c) 2012-2022 University of California, Los Angeles
  *
  * This file is part of ChronoSync, synchronization library for distributed realtime
  * applications for NDN.
@@ -27,18 +27,8 @@
 class Handler
 {
 public:
-  Handler(ndn::Face& face,
-          const Name& syncPrefix,
-          const Name& userPrefix)
-    : logic(face,
-            syncPrefix,
-            userPrefix,
-            bind(&Handler::onUpdate, this, _1))
-  {
-  }
-
-  void
-  onUpdate(const std::vector<MissingDataInfo>& v)
+  Handler(ndn::Face& face, const Name& syncPrefix, const Name& userPrefix)
+    : logic(face, syncPrefix, userPrefix, [] (auto&&...) {})
   {
   }
 
@@ -76,7 +66,7 @@
     userPrefix[1] = Name("/user1");
     userPrefix[2] = Name("/user2");
 
-    face = make_shared<ndn::Face>(ref(io));
+    face = std::make_shared<ndn::Face>(io);
   }
 
   Name syncPrefix;
@@ -92,7 +82,7 @@
 
 BOOST_AUTO_TEST_CASE(ThreeUserNode)
 {
-  handler = make_shared<Handler>(ref(*face), syncPrefix, userPrefix[0]);
+  handler = std::make_shared<Handler>(*face, syncPrefix, userPrefix[0]);
   handler->addUserNode(userPrefix[1]);
   handler->addUserNode(userPrefix[2]);
   handler->removeUserNode(userPrefix[0]);
diff --git a/tests/unit-tests/test-socket.cpp b/tests/unit-tests/test-socket.cpp
index 3b16939..67f1c3e 100644
--- a/tests/unit-tests/test-socket.cpp
+++ b/tests/unit-tests/test-socket.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
 /*
- * Copyright (c) 2012-2019 University of California, Los Angeles
+ * Copyright (c) 2012-2022 University of California, Los Angeles
  *
  * This file is part of ChronoSync, synchronization library for distributed realtime
  * applications for NDN.
@@ -48,7 +48,7 @@
              userPrefix,
              face,
              isNum ? bind(&SocketTestApp::fetchNumbers, this, _1) :
-                          bind(&SocketTestApp::fetchAll, this, _1),
+                     bind(&SocketTestApp::fetchAll, this, _1),
              Logic::DEFAULT_NAME,
              Logic::DEFAULT_VALIDATOR,
              Logic::DEFAULT_SYNC_INTEREST_LIFETIME,
@@ -63,14 +63,14 @@
     Name dataName(dataPacket.getName());
     string str2(reinterpret_cast<const char*>(dataPacket.getContent().value()),
                 dataPacket.getContent().value_size());
-    data.insert(make_pair(dataName, str2));
+    data.emplace(dataName, str2);
   }
 
   void
   set(Name name, const char* buf, int len)
   {
     string str2(buf, len);
-    data.insert(make_pair(name, str2));
+    data.emplace(name, str2);
   }
 
   void
@@ -139,7 +139,7 @@
   }
 
 public:
-  std::map<ndn::Name, string> data;
+  std::map<Name, string> data;
   uint32_t sum;
   Socket socket;
 };
@@ -194,7 +194,7 @@
   void
   createSocket(size_t idx, bool isNum)
   {
-    app[idx] = make_shared<SocketTestApp>(syncPrefix, userPrefix[idx], ref(*faces[idx]), isNum);
+    app[idx] = make_shared<SocketTestApp>(syncPrefix, userPrefix[idx], std::ref(*faces[idx]), isNum);
     sessionName[idx] = app[idx]->socket.getLogic().getSessionName();
   }