// last entry, snapshot 2
assertEquals(map2.lastEntry().getKey(), tree.lastEntry(snap2).getKey());
assertEquals(map2.lastEntry().getValue(), tree.lastEntry(snap2).getValue());
// first entry, snapshot 1
assertEquals(map1.firstEntry().getKey(), tree.firstEntry(snap1).getKey());
assertEquals(map1.firstEntry().getValue(), tree.firstEntry(snap1).getValue());
// last entry, snapshot 1
assertEquals(map1.lastEntry().getKey(), tree.lastEntry(snap1).getKey());
assertEquals(map1.lastEntry().getValue(), tree.lastEntry(snap1).getValue());