diff --git a/tests/unit-tests/ims/in-memory-storage-persistent.t.cpp b/tests/unit-tests/ims/in-memory-storage-persistent.t.cpp
index 9be6430..1ae637d 100644
--- a/tests/unit-tests/ims/in-memory-storage-persistent.t.cpp
+++ b/tests/unit-tests/ims/in-memory-storage-persistent.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2017 Regents of the University of California.
+ * Copyright (c) 2013-2018 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -48,7 +48,7 @@
     convert << i;
     Name name("/" + convert.str());
     shared_ptr<Data> data = makeData(name);
-    data->setFreshnessPeriod(time::milliseconds(5000));
+    data->setFreshnessPeriod(5000_ms);
     signData(data);
     ims.insert(*data);
   }