tests: sync common testing infrastructure with ndn-cxx

Change-Id: I6feab5247231abc35b8daa96bca21ad17c9cc4b3
diff --git a/tests/daemon/rib-io-fixture.hpp b/tests/daemon/rib-io-fixture.hpp
index 5fcefb6..f8660fd 100644
--- a/tests/daemon/rib-io-fixture.hpp
+++ b/tests/daemon/rib-io-fixture.hpp
@@ -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,
@@ -79,14 +79,11 @@
 
 /** \brief RibIoFixture that also overrides steady clock and system clock.
  */
-class RibIoTimeFixture : public RibIoFixture, public ClockFixture
+class RibIoTimeFixture : public ClockFixture, public RibIoFixture
 {
-protected:
-  RibIoTimeFixture();
-
 private:
   void
-  pollAfterClockTick() override;
+  afterTick() final;
 };
 
 } // namespace tests