diff --git a/tests/unit/util/ostream-joiner.t.cpp b/tests/unit/util/ostream-joiner.t.cpp
index 7e8e63f..2e7ac8f 100644
--- a/tests/unit/util/ostream-joiner.t.cpp
+++ b/tests/unit/util/ostream-joiner.t.cpp
@@ -26,8 +26,7 @@
 #include <numeric>
 #include <boost/test/tools/output_test_stream.hpp>
 
-namespace ndn {
-namespace tests {
+namespace ndn::tests {
 
 BOOST_AUTO_TEST_SUITE(Util)
 BOOST_AUTO_TEST_SUITE(TestOstreamJoiner)
@@ -69,5 +68,4 @@
 BOOST_AUTO_TEST_SUITE_END() // TestOstreamJoiner
 BOOST_AUTO_TEST_SUITE_END() // Util
 
-} // namespace tests
-} // namespace ndn
+} // namespace ndn::tests