tests: sync common testing infrastructure with ndn-cxx

Change-Id: I6feab5247231abc35b8daa96bca21ad17c9cc4b3
diff --git a/tests/clock-fixture.cpp b/tests/clock-fixture.cpp
index de55cf3..1691f89 100644
--- a/tests/clock-fixture.cpp
+++ b/tests/clock-fixture.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019,  Regents of the University of California,
+ * Copyright (c) 2014-2020,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -28,10 +28,9 @@
 namespace nfd {
 namespace tests {
 
-ClockFixture::ClockFixture(boost::asio::io_service& io)
+ClockFixture::ClockFixture()
   : m_steadyClock(make_shared<time::UnitTestSteadyClock>())
   , m_systemClock(make_shared<time::UnitTestSystemClock>())
-  , m_io(io)
 {
   time::setCustomClocks(m_steadyClock, m_systemClock);
 }
@@ -53,17 +52,9 @@
     m_systemClock->advance(t);
     total -= t;
 
-    pollAfterClockTick();
+    afterTick();
   }
 }
 
-void
-ClockFixture::pollAfterClockTick()
-{
-  if (m_io.stopped())
-    m_io.reset();
-  m_io.poll();
-}
-
 } // namespace tests
 } // namespace nfd