@Test
public void testOccurrenceRemoval() {

  TopicIF type = builder.makeTopic();
  
  TopicIF topic = builder.makeTopic();
  OccurrenceIF occ = builder.makeOccurrence(topic, type, "duplicate");
  
  occ = builder.makeOccurrence(topic, type, "duplicate");
  DuplicateSuppressionUtils.removeDuplicates(topic);
  Assert.assertTrue("duplicate occurrence were not removed",
         topic.getOccurrences().size() == 1);
}