builder.orderEntriesByValue(Ordering.natural()).build();
    assertMapEquals(keyOrdered, "four", 4, "one", 1);
    assertMapEquals(valueOrdered, "one", 1, "four", 4);
  }

  public void testBuilder_orderEntriesByValue_usedTwiceFails() {
    ImmutableBiMap.Builder<String, Integer> builder =
        new Builder<String, Integer>().orderEntriesByValue(Ordering.natural());
    assertThrows(

      for (Entry<? extends K, ? extends V> entry : entries) {
        put(entry);
      }
      return this;
    }

    @CanIgnoreReturnValue
    public Builder<K, V> orderEntriesByValue(Comparator<? super V> valueComparator) {
      checkState(this.valueComparator == null, "valueComparator was already set");
      this.valueComparator = checkNotNull(valueComparator, "valueComparator");
      return this;

  public void testBuilder_orderEntriesByValueFails() {
    ImmutableSortedMap.Builder<String, Integer> builder = ImmutableSortedMap.naturalOrder();
    assertThrows(
        UnsupportedOperationException.class, () -> builder.orderEntriesByValue(Ordering.natural()));
  }

  public void testBuilder_withImmutableEntry() {
    ImmutableSortedMap<String, Integer> map =