diff --git a/tests/unit/detail/packet-base.t.cpp b/tests/unit/detail/packet-base.t.cpp
new file mode 100644
index 0000000..41d47db
--- /dev/null
+++ b/tests/unit/detail/packet-base.t.cpp
@@ -0,0 +1,66 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2018 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#include "ndn-cxx/detail/packet-base.hpp"
+#include "ndn-cxx/interest.hpp"
+#include "ndn-cxx/lp/tags.hpp"
+
+#include "tests/boost-test.hpp"
+
+namespace ndn {
+namespace tests {
+
+BOOST_AUTO_TEST_SUITE(Detail)
+BOOST_AUTO_TEST_SUITE(TestPacketBase)
+
+BOOST_AUTO_TEST_CASE(CongestionMark)
+{
+  Interest interest;
+
+  BOOST_CHECK_EQUAL(interest.getCongestionMark(), 0);
+
+  auto tag = interest.getTag<lp::CongestionMarkTag>();
+  BOOST_CHECK(!tag);
+
+  interest.setCongestionMark(true);
+  tag = interest.getTag<lp::CongestionMarkTag>();
+  BOOST_REQUIRE(tag);
+  BOOST_CHECK_EQUAL(*tag, 1);
+
+  interest.setCongestionMark(false);
+  tag = interest.getTag<lp::CongestionMarkTag>();
+  BOOST_CHECK(!tag);
+
+  interest.setCongestionMark(300);
+  tag = interest.getTag<lp::CongestionMarkTag>();
+  BOOST_REQUIRE(tag);
+  BOOST_CHECK_EQUAL(*tag, 300);
+
+  interest.setCongestionMark(0);
+  tag = interest.getTag<lp::CongestionMarkTag>();
+  BOOST_CHECK(!tag);
+}
+
+BOOST_AUTO_TEST_SUITE_END() // TestPacketBase
+BOOST_AUTO_TEST_SUITE_END() // Detail
+
+} // namespace tests
+} // namespace ndn