@Test
public void lower() {

  Object key = new Object();
  Object value = new Object();
  Set<Object> set = new HashSet<Object>();
  set.add(value);
  doReturn(set).when(entry).getValue();
  doReturn(key).when(entry).getKey();
  doReturn(null).when(map).lowerEntry(key);
  List<Object> actualObjects = rangeIndex.lower(map, entry);
  assertEquals(value, actualObjects.get(0));
}