tests: namespace cleanup

Change-Id: I6b9ee82a4cb3b97c82ea111495ec07efddc8d825
diff --git a/tests/test-nlsr.cpp b/tests/test-nlsr.cpp
index adb321b..82c60ac 100644
--- a/tests/test-nlsr.cpp
+++ b/tests/test-nlsr.cpp
@@ -27,8 +27,7 @@
 
 #include <ndn-cxx/mgmt/nfd/face-event-notification.hpp>
 
-namespace nlsr {
-namespace test {
+namespace nlsr::tests {
 
 class MockNfdMgmtFixture : public IoKeyChainFixture
 {
@@ -598,5 +597,4 @@
 
 BOOST_AUTO_TEST_SUITE_END()
 
-} // namespace test
-} // namespace nlsr
+} // namespace nlsr::tests