diff --git a/tests/unit/util/simple-notification.hpp b/tests/unit/util/simple-notification.hpp
index ece2c48..239574b 100644
--- a/tests/unit/util/simple-notification.hpp
+++ b/tests/unit/util/simple-notification.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022 Regents of the University of California,
+ * Copyright (c) 2014-2023 Regents of the University of California,
  *                         Arizona Board of Regents,
  *                         Colorado State University,
  *                         University Pierre & Marie Curie, Sorbonne University,
@@ -30,9 +30,7 @@
 
 #include "ndn-cxx/encoding/block-helpers.hpp"
 
-namespace ndn {
-namespace util {
-namespace tests {
+namespace ndn::tests {
 
 class SimpleNotification
 {
@@ -82,8 +80,6 @@
   std::string m_message;
 };
 
-} // namespace tests
-} // namespace util
-} // namespace ndn
+} // namespace ndn::tests
 
 #endif // NDN_CXX_TESTS_UNIT_UTIL_SIMPLE_NOTIFICATION_HPP