tests: namespace cleanup

Change-Id: I6b9ee82a4cb3b97c82ea111495ec07efddc8d825
diff --git a/tests/test-adjacent.cpp b/tests/test-adjacent.cpp
index 5406096..083d448 100644
--- a/tests/test-adjacent.cpp
+++ b/tests/test-adjacent.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  The University of Memphis,
+ * Copyright (c) 2014-2024,  The University of Memphis,
  *                           Regents of the University of California
  *
  * This file is part of NLSR (Named-data Link State Routing).
@@ -23,8 +23,7 @@
 #include "adjacent.hpp"
 #include "tests/boost-test.hpp"
 
-namespace nlsr {
-namespace test {
+namespace nlsr::tests {
 
 BOOST_AUTO_TEST_SUITE(TestAdjacent)
 
@@ -103,5 +102,4 @@
 
 BOOST_AUTO_TEST_SUITE_END()
 
-} // namespace test
-} // namespace nlsr
+} // namespace nlsr::tests