diff --git a/tests/peek/ndnpeek.t.cpp b/tests/peek/ndnpeek.t.cpp
index c3979fd..6e8869f 100644
--- a/tests/peek/ndnpeek.t.cpp
+++ b/tests/peek/ndnpeek.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2022,  Arizona Board of Regents.
+ * Copyright (c) 2014-2023,  Arizona Board of Regents.
  *
  * This file is part of ndn-tools (Named Data Networking Essential Tools).
  * See AUTHORS.md for complete list of ndn-tools authors and contributors.
@@ -153,7 +153,7 @@
   BOOST_CHECK_EQUAL(interest.getMustBeFresh(), false);
   BOOST_CHECK_EQUAL(interest.getForwardingHint().empty(), true);
   BOOST_CHECK_EQUAL(interest.getInterestLifetime(), DEFAULT_INTEREST_LIFETIME);
-  BOOST_CHECK(interest.getHopLimit() == nullopt);
+  BOOST_CHECK(interest.getHopLimit() == std::nullopt);
   BOOST_CHECK(!interest.hasApplicationParameters());
   BOOST_CHECK(peek->getResult() == NdnPeek::Result::DATA);
 }
diff --git a/tests/test-common.cpp b/tests/test-common.cpp
index 6a994b0..89a764c 100644
--- a/tests/test-common.cpp
+++ b/tests/test-common.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,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -28,8 +28,8 @@
 namespace ndn::tests {
 
 shared_ptr<Interest>
-makeInterest(const Name& name, bool canBePrefix, optional<time::milliseconds> lifetime,
-             optional<Interest::Nonce> nonce)
+makeInterest(const Name& name, bool canBePrefix, std::optional<time::milliseconds> lifetime,
+             std::optional<Interest::Nonce> nonce)
 {
   auto interest = std::make_shared<Interest>(name);
   interest->setCanBePrefix(canBePrefix);
diff --git a/tests/test-common.hpp b/tests/test-common.hpp
index 5ff903a..a6edb6e 100644
--- a/tests/test-common.hpp
+++ b/tests/test-common.hpp
@@ -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,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -36,8 +36,8 @@
  */
 shared_ptr<Interest>
 makeInterest(const Name& name, bool canBePrefix = false,
-             optional<time::milliseconds> lifetime = nullopt,
-             optional<Interest::Nonce> nonce = nullopt);
+             std::optional<time::milliseconds> lifetime = std::nullopt,
+             std::optional<Interest::Nonce> nonce = std::nullopt);
 
 /**
  * \brief Create a Data with a null (i.e., empty) signature
@@ -71,7 +71,7 @@
 
 /**
  * \brief Replace a name component in a packet
- * \param[inout] pkt the packet
+ * \param[in,out] pkt the packet
  * \param index the index of the name component to replace
  * \param args arguments to name::Component constructor
  */