"estimated size of trySplit result (%s) is larger than original size (%s)",
                trySplit.estimateSize(), originalSize));
      }
    }
    if (subsized) {
      if (trySplit != null) {
        assertEquals(
            "sum of estimated sizes of trySplit and original spliterator after trySplit",
            originalSize,
            trySplit.estimateSize() + spliterator.estimateSize());
      } else {

        delegate.forEachRemaining((IntConsumer) i -> action.accept(function.apply(i)));
      }

      @Override
      @CheckForNull
      public Spliterator<T> trySplit() {
        Spliterator.OfInt split = delegate.trySplit();
        return (split == null) ? null : new WithCharacteristics(split);
      }

      @Override
      public long estimateSize() {
        return delegate.estimateSize();
      }

            .put(2, 2)
            .put(3, 3)
            .put(4, 4)
            .put(5, 5)
            .put(6, 6)
            .buildOrThrow();
    assertNotNull(map.keySet().spliterator().trySplit());
  }

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            ImmutableMap.of(),
            ImmutableMap.builder().buildOrThrow(),