diff --git a/tests/unit/util/config-file.t.cpp b/tests/unit/util/config-file.t.cpp
index 78b80be..9e098c1 100644
--- a/tests/unit/util/config-file.t.cpp
+++ b/tests/unit/util/config-file.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2021 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -24,6 +24,7 @@
 #include "tests/boost-test.hpp"
 #include "tests/unit/test-home-env-saver.hpp"
 
+#include <boost/filesystem/operations.hpp>
 #include <cstdlib>
 
 namespace ndn {