Migrate to C++17 and misc code cleanups

Change-Id: I6b63385c92361a7ef5803d2bfd00f39c77e88d34
diff --git a/tests/integrated/test-basic-command-insert-delete.cpp b/tests/integrated/test-basic-command-insert-delete.cpp
index 5ed5b9b..55d6e65 100644
--- a/tests/integrated/test-basic-command-insert-delete.cpp
+++ b/tests/integrated/test-basic-command-insert-delete.cpp
@@ -35,8 +35,7 @@
 #include <boost/mpl/vector.hpp>
 #include <boost/test/unit_test.hpp>
 
-namespace repo {
-namespace tests {
+namespace repo::tests {
 
 using ndn::time::milliseconds;
 
@@ -288,5 +287,4 @@
 
 BOOST_AUTO_TEST_SUITE_END()
 
-} // namespace tests
-} // namespace repo
+} // namespace repo::tests