diff --git a/tests/unit-tests/unit-test-time-fixture.hpp b/tests/unit-tests/unit-test-time-fixture.hpp
index 8d7ac17..9f43258 100644
--- a/tests/unit-tests/unit-test-time-fixture.hpp
+++ b/tests/unit-tests/unit-test-time-fixture.hpp
@@ -29,6 +29,8 @@
 namespace ndn {
 namespace tests {
 
+/** \brief a test fixture that overrides steady clock and system clock
+ */
 class UnitTestTimeFixture
 {
 public:
@@ -44,12 +46,47 @@
     time::setCustomClocks(nullptr, nullptr);
   }
 
+  /** \brief advance steady and system clocks
+   *
+   *  Clocks are advanced in increments of \p tick for \p nTicks ticks.
+   *  After each tick, io_service is polled to process pending I/O events.
+   *
+   *  Exceptions thrown during I/O events are propagated to the caller.
+   *  Clock advancing would stop in case of an exception.
+   */
   void
   advanceClocks(const time::nanoseconds& tick, size_t nTicks = 1)
   {
-    for (size_t i = 0; i < nTicks; ++i) {
-      steadyClock->advance(tick);
-      systemClock->advance(tick);
+    this->advanceClocks(tick, tick * nTicks);
+  }
+
+  /** \brief advance steady and system clocks
+   *
+   *  Clocks are advanced in increments of \p tick for \p total time.
+   *  The last increment might be shorter than \p tick.
+   *  After each tick, io_service is polled to process pending I/O events.
+   *
+   *  Exceptions thrown during I/O events are propagated to the caller.
+   *  Clock advancing would stop in case of an exception.
+   */
+  void
+  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 (io.stopped())
         io.reset();