tests+tools: follow DummyClientFace namespace change

Change-Id: I28f02aa29cd7c0c094234ce6e3f87b54e3468651
diff --git a/tests/unit/access-manager.t.cpp b/tests/unit/access-manager.t.cpp
index dbbae40..f8b110b 100644
--- a/tests/unit/access-manager.t.cpp
+++ b/tests/unit/access-manager.t.cpp
@@ -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
  *
  * NAC library is free software: you can redistribute it and/or modify it under the
  * terms of the GNU Lesser General Public License as published by the Free Software
@@ -26,9 +26,7 @@
 #include <ndn-cxx/util/dummy-client-face.hpp>
 #include <ndn-cxx/util/string-helper.hpp>
 
-namespace ndn {
-namespace nac {
-namespace tests {
+namespace ndn::nac::tests {
 
 class AccessManagerFixture : public IoKeyChainFixture
 {
@@ -50,7 +48,7 @@
   }
 
 public:
-  util::DummyClientFace face;
+  DummyClientFace face;
   Identity accessIdentity;
   Identity nacIdentity;
   std::vector<Identity> userIdentities;
@@ -135,6 +133,4 @@
 
 BOOST_AUTO_TEST_SUITE_END()
 
-} // namespace tests
-} // namespace nac
-} // namespace ndn
+} // namespace ndn::nac::tests