diff --git a/tests/unit/net/dns.t.cpp b/tests/unit/net/dns.t.cpp
index b6a24b5..ac734dd 100644
--- a/tests/unit/net/dns.t.cpp
+++ b/tests/unit/net/dns.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2022 Regents of the University of California.
+ * Copyright (c) 2013-2023 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -26,10 +26,9 @@
 
 #include <boost/asio/io_service.hpp>
 
-namespace ndn {
-namespace dns {
-namespace tests {
+namespace ndn::tests {
 
+using namespace ndn::dns;
 using boost::asio::ip::address_v4;
 using boost::asio::ip::address_v6;
 
@@ -169,6 +168,4 @@
 BOOST_AUTO_TEST_SUITE_END() // TestDns
 BOOST_AUTO_TEST_SUITE_END() // Net
 
-} // namespace tests
-} // namespace dns
-} // namespace ndn
+} // namespace ndn::tests