diff --git a/tests/test-common.cpp b/tests/test-common.cpp
new file mode 100644
index 0000000..7041406
--- /dev/null
+++ b/tests/test-common.cpp
@@ -0,0 +1,65 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2020 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx 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
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#include "tests/test-common.hpp"
+
+namespace ndn {
+namespace tests {
+
+shared_ptr<Interest>
+makeInterest(const Name& name, bool canBePrefix, optional<time::milliseconds> lifetime,
+             optional<Interest::Nonce> nonce)
+{
+  auto interest = std::make_shared<Interest>(name);
+  interest->setCanBePrefix(canBePrefix);
+  if (lifetime) {
+    interest->setInterestLifetime(*lifetime);
+  }
+  interest->setNonce(nonce);
+  return interest;
+}
+
+shared_ptr<Data>
+makeData(const Name& name)
+{
+  auto data = std::make_shared<Data>(name);
+  return signData(data);
+}
+
+Data&
+signData(Data& data)
+{
+  data.setSignatureInfo(SignatureInfo(tlv::NullSignature));
+  data.setSignatureValue(std::make_shared<Buffer>());
+  data.wireEncode();
+  return data;
+}
+
+lp::Nack
+makeNack(Interest interest, lp::NackReason reason)
+{
+  lp::Nack nack(std::move(interest));
+  nack.setReason(reason);
+  return nack;
+}
+
+} // namespace tests
+} // namespace ndn