diff --git a/tests/unit-tests/model/ndn-block-header.t.cpp b/tests/unit-tests/model/ndn-block-header.t.cpp
index 5dc65f1..474f7e5 100644
--- a/tests/unit-tests/model/ndn-block-header.t.cpp
+++ b/tests/unit-tests/model/ndn-block-header.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2011-2015  Regents of the University of California.
+ * Copyright (c) 2011-2019  Regents of the University of California.
  *
  * This file is part of ndnSIM. See AUTHORS for complete list of ndnSIM authors and
  * contributors.
@@ -21,6 +21,7 @@
 #include "helper/ndn-stack-helper.hpp"
 
 #include <ndn-cxx/lp/packet.hpp>
+#include <ndn-cxx/encoding/block.hpp>
 
 #include "ns3/ndnSIM/NFD/daemon/face/transport.hpp"
 #include "ns3/packet.h"
@@ -30,6 +31,8 @@
 namespace ns3 {
 namespace ndn {
 
+using ::ndn::operator "" _block;
+
 BOOST_FIXTURE_TEST_SUITE(ModelNdnBlockHeader, CleanupFixture)
 
 class EnablePacketPrintingFixture
@@ -142,8 +145,8 @@
     BOOST_CHECK(output.is_equal("ns3::ndn::Packet (NDNLP(fragment 1 out of 2))"));
   }
 
-  ::ndn::Buffer buf(10);
-  lpPacket.set<::ndn::lp::FragmentField>(std::make_pair(buf.begin(), buf.end()));
+  Block unknown = "8808 0000 0000 0000 0000"_block;
+  lpPacket.set<::ndn::lp::FragmentField>(std::make_pair(unknown.begin(), unknown.end()));
   lpPacket.remove<::ndn::lp::FragCountField>();
   lpPacket.remove<::ndn::lp::FragIndexField>();
 
diff --git a/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp b/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
index 7150139..3e8804c 100644
--- a/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
+++ b/tests/unit-tests/utils/tracers/ndn-app-delay-tracer.t.cpp
@@ -89,12 +89,12 @@
 
   BOOST_CHECK_EQUAL(buffer.str(),
                     R"STR(Time	Node	AppId	SeqNo	Type	DelayS	DelayUS	RetxCount	HopCount
-0.0417968	1	0	0	LastDelay	0.0417968	41796.8	1	2
-0.0417968	1	0	0	FullDelay	0.0417968	41796.8	1	2
-2	2	0	0	LastDelay	0	0	1	0
-2	2	0	0	FullDelay	0	0	1	0
-3.0209	2	0	1	LastDelay	0.0208984	20898.4	1	1
-3.0209	2	0	1	FullDelay	0.0208984	20898.4	1	1
+0.0417744	1	0	0	LastDelay	0.0417744	41774.4	1	2
+0.0417744	1	0	0	FullDelay	0.0417744	41774.4	1	2
+2	2	0	0	LastDelay	0	0	1	1
+2	2	0	0	FullDelay	0	0	1	1
+3.02089	2	0	1	LastDelay	0.0208872	20887.2	1	1
+3.02089	2	0	1	FullDelay	0.0208872	20887.2	1	1
 )STR");
 }
 
@@ -116,8 +116,8 @@
 
   BOOST_CHECK_EQUAL(buffer.str(),
     R"STR(Time	Node	AppId	SeqNo	Type	DelayS	DelayUS	RetxCount	HopCount
-0.0417968	1	0	0	LastDelay	0.0417968	41796.8	1	2
-0.0417968	1	0	0	FullDelay	0.0417968	41796.8	1	2
+0.0417744	1	0	0	LastDelay	0.0417744	41774.4	1	2
+0.0417744	1	0	0	FullDelay	0.0417744	41774.4	1	2
 )STR");
 }
 
@@ -136,10 +136,10 @@
 
   BOOST_CHECK_EQUAL(buffer.str(),
     R"STR(Time	Node	AppId	SeqNo	Type	DelayS	DelayUS	RetxCount	HopCount
-2	2	0	0	LastDelay	0	0	1	0
-2	2	0	0	FullDelay	0	0	1	0
-3.0209	2	0	1	LastDelay	0.0208984	20898.4	1	1
-3.0209	2	0	1	FullDelay	0.0208984	20898.4	1	1
+2	2	0	0	LastDelay	0	0	1	1
+2	2	0	0	FullDelay	0	0	1	1
+3.02089	2	0	1	LastDelay	0.0208872	20887.2	1	1
+3.02089	2	0	1	FullDelay	0.0208872	20887.2	1	1
 )STR");
 }
 
@@ -154,10 +154,10 @@
   tracer = nullptr; // destroy tracer
 
   BOOST_CHECK(output->is_equal(
-    R"STR(2	2	0	0	LastDelay	0	0	1	0
-2	2	0	0	FullDelay	0	0	1	0
-3.0209	2	0	1	LastDelay	0.0208984	20898.4	1	1
-3.0209	2	0	1	FullDelay	0.0208984	20898.4	1	1
+    R"STR(2	2	0	0	LastDelay	0	0	1	1
+2	2	0	0	FullDelay	0	0	1	1
+3.02089	2	0	1	LastDelay	0.0208872	20887.2	1	1
+3.02089	2	0	1	FullDelay	0.0208872	20887.2	1	1
 )STR"));
 }