assertSame(comparator, map.comparator());
  }

  // TODO(b/172823566): Use mainline testToImmutableSortedMap once CollectorTester is usable.
  public void testToImmutableSortedMap_java7_combine() {
    ImmutableSortedMap.Builder<String, Integer> zis =
        ImmutableSortedMap.<String, Integer>naturalOrder().put("one", 1).put("four", 4);
    ImmutableSortedMap.Builder<String, Integer> zat =