### Question:
MinTimestampTracker implements TimestampTracker<E> { public void removeElement(final Stamped<E> elem) { if (elem == null) { return; } if (ascendingSubsequence.peekFirst() == elem) { ascendingSubsequence.removeFirst(); } if (ascendingSubsequence.isEmpty()) { lastKnownTime = elem.timestamp; } }  void addElement(final Stamped<E> elem); void removeElement(final Stamped<E> elem); int size(); long get();  }### Answer:
@Test public void shouldIgnoreNullRecordOnRemove() throws Exception { tracker.removeElement(null); }