@Test
public void between() {

  Comparable<Object> key = comparable;
  Object value = new Object();
  Set<Object> set = new HashSet<Object>();
  set.add(value);
  doReturn(set).when(entry).getValue();
  doReturn(key).when(entry).getKey();
  doReturn(entry).when(map).higherEntry(lowerBound);
  doReturn(-1).doReturn(1).when(key).compareTo(upperBound);
  doReturn(null).when(map).higherEntry(key);
  List<Object> list = rangeIndex.between(lowerBound, upperBound);
  assertTrue(list.contains(value));
}