diff --git a/tests/unit/security/pib/key.t.cpp b/tests/unit/security/pib/key.t.cpp
index 4d1da0c..5273436 100644
--- a/tests/unit/security/pib/key.t.cpp
+++ b/tests/unit/security/pib/key.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2022 Regents of the University of California.
+ * Copyright (c) 2013-2023 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -25,13 +25,11 @@
 #include "tests/boost-test.hpp"
 #include "tests/unit/security/pib/pib-data-fixture.hpp"
 
-namespace ndn {
-namespace security {
-namespace pib {
-namespace tests {
+namespace ndn::tests {
+
+using namespace ndn::security::pib;
 
 BOOST_AUTO_TEST_SUITE(Security)
-BOOST_AUTO_TEST_SUITE(Pib)
 BOOST_FIXTURE_TEST_SUITE(TestKey, PibDataFixture)
 
 BOOST_AUTO_TEST_CASE(ValidityChecking)
@@ -41,8 +39,7 @@
   BOOST_TEST(key == Key());
   BOOST_CHECK_THROW(key.getName(), std::domain_error);
 
-  auto impl = std::make_shared<detail::KeyImpl>(id1Key1Name, id1Key1,
-                                                makePibWithKey(id1Key1Name, id1Key1));
+  auto impl = std::make_shared<KeyImpl>(id1Key1Name, id1Key1, makePibWithKey(id1Key1Name, id1Key1));
   key = Key(impl);
   BOOST_TEST(key);
   BOOST_TEST(key != Key());
@@ -53,13 +50,12 @@
   BOOST_CHECK_THROW(key.getName(), std::domain_error);
 }
 
-// pib::Key is a wrapper of pib::detail::KeyImpl. Since the functionality of KeyImpl is
-// already tested in key-impl.t.cpp, we only test the shared property of pib::Key in
-// this test case.
+// pib::Key is a wrapper of pib::KeyImpl. Since the functionality of KeyImpl is
+// already tested in key-impl.t.cpp, we only test the shared property of pib::Key
+// in this test case.
 BOOST_AUTO_TEST_CASE(SharedImpl)
 {
-  auto keyImpl = std::make_shared<detail::KeyImpl>(id1Key1Name, id1Key1,
-                                                   makePibWithKey(id1Key1Name, id1Key1));
+  auto keyImpl = std::make_shared<KeyImpl>(id1Key1Name, id1Key1, makePibWithKey(id1Key1Name, id1Key1));
   Key key1(keyImpl);
   Key key2(keyImpl);
 
@@ -68,12 +64,12 @@
   BOOST_TEST(Key() != key2);
   BOOST_TEST(Key() == Key());
 
-  BOOST_CHECK_THROW(key2.getCertificate(id1Key1Cert1.getName()), pib::Pib::Error);
+  BOOST_CHECK_THROW(key2.getCertificate(id1Key1Cert1.getName()), Pib::Error);
   key1.addCertificate(id1Key1Cert1);
   BOOST_TEST(key2.getCertificate(id1Key1Cert1.getName()) == id1Key1Cert1);
 
   key2.removeCertificate(id1Key1Cert1.getName());
-  BOOST_CHECK_THROW(key1.getCertificate(id1Key1Cert1.getName()), pib::Pib::Error);
+  BOOST_CHECK_THROW(key1.getCertificate(id1Key1Cert1.getName()), Pib::Error);
 
   key1.setDefaultCertificate(id1Key1Cert1);
   BOOST_TEST(key2.getDefaultCertificate() == id1Key1Cert1);
@@ -81,6 +77,10 @@
 
 BOOST_AUTO_TEST_CASE(Helpers)
 {
+  using ndn::security::constructKeyName;
+  using ndn::security::isValidKeyName;
+  using ndn::security::extractIdentityFromKeyName;
+
   BOOST_CHECK_EQUAL(constructKeyName("/hello", name::Component("world")), "/hello/KEY/world");
 
   BOOST_CHECK_EQUAL(isValidKeyName("/hello"), false);
@@ -98,10 +98,6 @@
 }
 
 BOOST_AUTO_TEST_SUITE_END() // TestKey
-BOOST_AUTO_TEST_SUITE_END() // Pib
 BOOST_AUTO_TEST_SUITE_END() // Security
 
-} // namespace tests
-} // namespace pib
-} // namespace security
-} // namespace ndn
+} // namespace ndn::tests