new ClassSanityTester().forAllPublicStaticMethods(Functions.class).testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  // (I suspect that this and the other similar failures happen with ArbitraryInstances proxies.)
  public void testEqualsAndSerializable() throws Exception {

    new ClassSanityTester().forAllPublicStaticMethods(Functions.class).testNulls();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection
  @AndroidIncompatible // TODO(cpovirk): ClassNotFoundException: com.google.common.base.Function
  // (I suspect that this and the other similar failures happen with ArbitraryInstances proxies.)
  public void testEqualsAndSerializable() throws Exception {

    if (size == 0) {
      // We avoid allocating anything.
      return of();
    }
    // Collection<E>.toArray() is required to contain only E instances, and all we do is read them.
    // TODO(cpovirk): Consider using Object[] anyway.
    E[] array = (E[]) elements.toArray();
    /*
     * For a Set, we guess that it contains no duplicates. That's just a guess for purpose of

    // first range closed end, second range closed start
    assertEquals(Range.open(2, 4), Range.atMost(2).gap(closedRange));
    assertEquals(Range.open(2, 4), closedRange.gap(Range.atMost(2)));
  }

  // TODO(cpovirk): More extensive testing of gap().

  public void testSpan_general() {
    Range<Integer> range = Range.closed(4, 8);

    // separate below
    assertEquals(Range.closed(0, 8), range.span(Range.closed(0, 2)));

  // The comparator used by this map.  It's the same as that of sortedDelegate,
  // except that when sortedDelegate's comparator is null, it points to a
  // non-null instance of Ordering.natural().
  // (cpovirk: Is sortedDelegate's comparator really ever null?)
  // The comparator will likely also differ because of our nullAccepting hack.
  // See the bottom of the file for more information about it.

      case 1:
        Entry<? extends K, ? extends V> entry = getOnlyElement(entries);
        return of((K) entry.getKey(), (V) entry.getValue());
      default:
        @SuppressWarnings("unchecked") // TODO(cpovirk): Consider storing an Entry<?, ?>[].
        Entry<K, V>[] entryArray = entries.toArray((Entry<K, V>[]) new Entry<?, ?>[entries.size()]);
        return new RegularImmutableMap<K, V>(throwIfDuplicateKeys, entryArray);
    }

    results = service.invokeAll(callables, 1, SECONDS);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);

    /*
     * TODO(cpovirk): move ForwardingTestCase somewhere common, and use it to
     * test the forwarded methods
     */
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.

    HashTestUtils.assertInvariants(Hashing.fingerprint2011());
    assertEquals("Hashing.fingerprint2011()", Hashing.fingerprint2011().toString());
  }

  @AndroidIncompatible // slow TODO(cpovirk): Maybe just reduce iterations under Android.
  public void testGoodFastHash() {
    for (int i = 1; i < 200; i += 17) {
      HashFunction hasher = Hashing.goodFastHash(i);
      assertTrue(hasher.bits() >= i);

    results = service.invokeAll(callables, 1, SECONDS);
    assertThat(getOnlyElement(results)).isInstanceOf(TrustedListenableFutureTask.class);

    /*
     * TODO(cpovirk): move ForwardingTestCase somewhere common, and use it to
     * test the forwarded methods
     */
  }

  @AndroidIncompatible // Mocking ExecutorService is forbidden there. TODO(b/218700094): Don't mock.

    HashTestUtils.assertInvariants(Hashing.fingerprint2011());
    assertEquals("Hashing.fingerprint2011()", Hashing.fingerprint2011().toString());
  }

  @AndroidIncompatible // slow TODO(cpovirk): Maybe just reduce iterations under Android.
  public void testGoodFastHash() {
    for (int i = 1; i < 200; i += 17) {
      HashFunction hasher = Hashing.goodFastHash(i);
      assertTrue(hasher.bits() >= i);