diff --git a/tests/unit-test-common-fixtures.cpp b/tests/unit-test-common-fixtures.cpp
new file mode 100644
index 0000000..f16e027
--- /dev/null
+++ b/tests/unit-test-common-fixtures.cpp
@@ -0,0 +1,82 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2016,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NDNS (Named Data Networking Domain Name Service) and is
+ * based on the code written as part of NFD (Named Data Networking Daemon).
+ * See AUTHORS.md for complete list of NDNS authors and contributors.
+ *
+ * NDNS is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NDNS 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NDNS, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "test-common.hpp"
+
+namespace ndn {
+namespace ndns {
+namespace tests {
+
+BaseFixture::BaseFixture()
+{
+}
+
+UnitTestTimeFixture::UnitTestTimeFixture()
+  : steadyClock(make_shared<time::UnitTestSteadyClock>())
+  , systemClock(make_shared<time::UnitTestSystemClock>())
+{
+  time::setCustomClocks(steadyClock, systemClock);
+}
+
+UnitTestTimeFixture::~UnitTestTimeFixture()
+{
+  time::setCustomClocks(nullptr, nullptr);
+}
+
+void
+UnitTestTimeFixture::advanceClocks(const time::nanoseconds& tick, size_t nTicks)
+{
+  this->advanceClocks(tick, tick * nTicks);
+}
+
+void
+UnitTestTimeFixture::advanceClocks(const time::nanoseconds& tick, const time::nanoseconds& total)
+{
+  BOOST_ASSERT(tick > time::nanoseconds::zero());
+  BOOST_ASSERT(total >= time::nanoseconds::zero());
+
+  time::nanoseconds remaining = total;
+  while (remaining > time::nanoseconds::zero()) {
+    if (remaining >= tick) {
+      steadyClock->advance(tick);
+      systemClock->advance(tick);
+      remaining -= tick;
+    }
+    else {
+      steadyClock->advance(remaining);
+      systemClock->advance(remaining);
+      remaining = time::nanoseconds::zero();
+    }
+
+    if (m_io.stopped())
+      m_io.reset();
+    m_io.poll();
+  }
+}
+
+} // namespace tests
+} // namespace ndns
+} // namespace ndn