assertEquals(mapEntry("three", 5), map.subMap("one", false, "zzz", true).pollLastEntry());
    assertThat(strings).contains("one");
  }

  @GwtIncompatible // NavigableMap
  public void testAsMapNavigableSubViewKeySetsDoNotSupportAdd() {
    NavigableMap<String, Integer> map = Maps.asMap(Sets.<String>newTreeSet(), LENGTH_FUNCTION);
    assertThrows(UnsupportedOperationException.class, () -> map.descendingKeySet().add("a"));