@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);
    }
  }

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cpovirk <******@****.***> 1754582511 -0700

                    SafeTreeMap<String, String> map = new SafeTreeMap<>();
                    putEntries(map, entries);
                    return Maps.unmodifiableNavigableMap(map);
                  }
                })
            .named("unmodifiableNavigableMap[SafeTreeMap]")
            .withFeatures(
                CollectionSize.ANY, MapFeature.ALLOWS_NULL_VALUES, CollectionFeature.SERIALIZABLE)
            .createTestSuite());

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cpovirk <******@****.***> 1742475744 -0700

cpovirk <******@****.***> 1740000085 -0800