Set<Set<Integer>> reverse = powerSet(ImmutableSet.copyOf(elements.asList().reverse()));
    new EqualsTester().addEqualityGroup(forward, reverse).testEquals();
  }

  /**
   * Test that a hash code miscomputed by "input.hashCode() * tooFarValue / 2" is correct under our
   * {@code hashCode} implementation.
   */
  public void testPowerSetHashCode_inputHashCodeTimesTooFarValueIsZero() {

    assertNull(segment.get(key, hash));

    // count == 0
    table.set(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));

    assertNull(segment.get(key, hash));

    // count == 0
    table.set(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));

      }
    } else {
      assertEquals(expectedHashCode.asLong.longValue(), hash.asLong());
    }
    assertEquals(expectedHashCode.toString, hash.toString());
    assertSideEffectFree(hash);
    assertReadableBytes(hash);
  }

  private static void assertSideEffectFree(HashCode hash) {
    byte[] original = hash.asBytes();
    byte[] mutated = hash.asBytes();
    mutated[0]++;

    if (key == null) {
      return null;
    }
    int hash = hash(key);
    return segmentFor(hash).get(key, hash);
  }

  @CanIgnoreReturnValue // TODO(b/27479612): consider removing this
  V get(K key, CacheLoader<? super K, V> loader) throws ExecutionException {
    int hash = hash(checkNotNull(key));
    return segmentFor(hash).get(key, hash, loader);
  }

  @CheckForNull

          new Sink(4).putUnencodedChars(s).hash(),
          new Sink(4).putBytes(s.getBytes(UTF_16LE)).hash());
      assertEquals(
          new Sink(4).putUnencodedChars(s).hash(), new Sink(4).putString(s, UTF_16LE).hash());
    }
  }

  public void testFloat() {
    Sink sink = new Sink(4);
    sink.putFloat(Float.intBitsToFloat(0x04030201));
    HashCode unused = sink.hash();
    sink.assertInvariants(4);

    assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
    assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
    assertThat(c.asMap().computeIfAbsent("hash-1", k -> "")).isEqualTo("");
    assertThat(c.size()).isEqualTo(1);
    assertThat(c.asMap().computeIfAbsent("hash-2", k -> "")).isEqualTo("");
  }

  public void testComputeEviction() {
    // b/80241237

      assertEquals(
          new TestHasher().putUnencodedChars(s).hash(),
          new TestHasher().putBytes(s.getBytes(UTF_16LE)).hash());
      assertEquals(
          new TestHasher().putUnencodedChars(s).hash(),
          new TestHasher().putString(s, UTF_16LE).hash());
    }
  }

  public void testFloat() {
    TestHasher hasher = new TestHasher();

   * exists, a CAS is tried.  Retries proceed by "double hashing",
   * using a secondary hash (Marsaglia XorShift) to try to find a
   * free slot.
   *
   * The table size is capped because, when there are more threads
   * than CPUs, supposing that each thread were bound to a CPU,
   * there would exist a perfect hash function mapping threads to
   * slots that eliminates collisions. When we reach capacity, we

    /**
     * Checks the whole hash table for poor hash distribution. Takes O(n) in the worst case, O(n /
     * log n) on average.
     *
     * <p>The online hash flooding detecting in RegularSetBuilderImpl.add can detect e.g. many
     * exactly matching hash codes, which would cause construction to take O(n^2), but can't detect