@Override
              protected NavigableMap<String, String> create(Entry<String, String>[] entries) {
                return Collections.unmodifiableNavigableMap(populate(new TreeMap<>(), entries));
              }
            })
        .named("unmodifiableNavigableMap/TreeMap, natural")
        .withFeatures(
            MapFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,

      NavigableMap<K, V> unmodifiableNavigableMap(NavigableMap<K, ? extends V> map) {
    checkNotNull(map);
    if (map instanceof UnmodifiableNavigableMap) {
      @SuppressWarnings("unchecked") // covariant
      NavigableMap<K, V> result = (NavigableMap<K, V>) map;
      return result;
    } else {
      return new UnmodifiableNavigableMap<>(map);
    }
  }

      NavigableMap<K, V> unmodifiableNavigableMap(NavigableMap<K, ? extends V> map) {
    checkNotNull(map);
    if (map instanceof UnmodifiableNavigableMap) {
      @SuppressWarnings("unchecked") // covariant
      NavigableMap<K, V> result = (NavigableMap<K, V>) map;
      return result;
    } else {
      return new UnmodifiableNavigableMap<>(map);
    }
  }

cpovirk <******@****.***> 1771874087 -0800

cpovirk <******@****.***> 1771874087 -0800

import static com.google.common.collect.Maps.immutableEntry;
import static com.google.common.collect.Maps.transformEntries;
import static com.google.common.collect.Maps.transformValues;
import static com.google.common.collect.Maps.unmodifiableNavigableMap;
import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.testing.Helpers.mapEntry;
import static com.google.common.truth.Truth.assertThat;