@Test
public void testGetInstancesOfTopic() throws IOException {

  load(testdataDirectory, "small-test.ltm");
  Collection instances = ClassInstanceUtils.getInstancesOf(topicmap.getTopics(),
                                                           getTopicById("person"));
  Assert.assertTrue("wrong number of instances", instances.size() == 3);
  Assert.assertTrue("instances does not contain 'lmg'",
             instances.contains(getTopicById("lmg")));
  Assert.assertTrue("instances does not contain 'gra'",
             instances.contains(getTopicById("gra")));
  Assert.assertTrue("instances does not contain 'grove'",
             instances.contains(getTopicById("grove")));
}