@Test
public void testFloorEntry() {

    IncrementalSortMap<Integer, String> map = map5();
    Map.Entry e1 = map.floorEntry(three);
    assertEquals(three, e1.getKey());
    Map.Entry e2 = map.floorEntry(six);
    assertEquals(five, e2.getKey());
    Map.Entry e3 = map.floorEntry(one);
    assertEquals(one, e3.getKey());
    Map.Entry e4 = map.floorEntry(zero);
    assertNull(e4);
}