@Test
public void testOccurrenceReifiers() {

  TopicIF type = builder.makeTopic();
  TopicIF topic = builder.makeTopic();
  OccurrenceIF occ = builder.makeOccurrence(topic, type, "test");
  TopicIF r1 = builder.makeTopic();
  occ.setReifier(r1);
  builder.makeTopicName(r1, "r1");
  
  OccurrenceIF occ2 = builder.makeOccurrence(topic, type, "test");
  TopicIF r2 = builder.makeTopic();
  occ2.setReifier(r2);
  builder.makeTopicName(r2, "r2");
  DuplicateSuppressionUtils.removeDuplicates(topic);
  Assert.assertTrue("duplicate occurrences were not removed",
             topic.getOccurrences().size() == 1);
  occ = (OccurrenceIF) topic.getOccurrences().iterator().next();
  r1 = occ.getReifier();
  Assert.assertTrue("reifier was lost", r1 != null);
  Assert.assertTrue("reifiers were not merged", r1.getTopicNames().size() == 2);
}