ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);
    assertThat(startupTimes.get(b)).isAtLeast(353);
  }

  public void testServiceStartupDurations() {
    if (isWindows() && isJava8()) {
      // Flaky there: https://github.com/google/guava/pull/6731#issuecomment-1736298607

    assertThat(stats.missRate()).isEqualTo(1.0);
    assertThat(stats.loadCount()).isEqualTo(1);
    long totalLoadTime = stats.totalLoadTime();
    assertThat(totalLoadTime).isAtLeast(0);
    assertThat(stats.averageLoadPenalty()).isAtLeast(0.0);
    assertThat(stats.evictionCount()).isEqualTo(0);

    cache.getUnchecked(one);
    stats = cache.stats();
    assertThat(stats.requestCount()).isEqualTo(2);

    assertThat(stats.missRate()).isEqualTo(1.0);
    assertThat(stats.loadCount()).isEqualTo(1);
    long totalLoadTime = stats.totalLoadTime();
    assertThat(totalLoadTime).isAtLeast(0);
    assertThat(stats.averageLoadPenalty()).isAtLeast(0.0);
    assertThat(stats.evictionCount()).isEqualTo(0);

    cache.getUnchecked(one);
    stats = cache.stats();
    assertThat(stats.requestCount()).isEqualTo(2);

    ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);
    assertThat(startupTimes.get(b)).isAtLeast(353);
  }

  public void testServiceStartupDurations() {
    if (isWindows() && isJava8()) {
      // Flaky there: https://github.com/google/guava/pull/6731#issuecomment-1736298607

    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      BigInteger result = BigIntegerMath.ceilingPowerOfTwo(x);
      assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertThat(result).isAtLeast(x);
      assertThat(result).isLessThan(x.add(x));
    }
  }

  public void testFloorPowerOfTwo() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {

      int drained = drain(q, new ArrayList<>(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

      assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);

      // If even the first one wasn't there, clean up so that the next test doesn't see an element.
      producerThread.cancel(true);
      producer.doneProducing.await();
      if (drained == 0) {

        assertThat(BloomFilter.optimalNumOfBits(n, fpp)).isAtLeast(0);
      }
    }

    // some random values
    Random random = new Random(0);
    for (int repeats = 0; repeats < 10000; repeats++) {
      assertThat(BloomFilter.optimalNumOfBits(random.nextInt(1 << 16), random.nextDouble()))
          .isAtLeast(0);
    }

    byte[] mutated = hash.asBytes();
    mutated[0]++;
    assertThat(hash.asBytes()).isEqualTo(original);
  }

  private static void assertReadableBytes(HashCode hashCode) {
    assertThat(hashCode.bits()).isAtLeast(32); // sanity
    byte[] hashBytes = hashCode.asBytes();
    int totalBytes = hashCode.bits() / 8;

    for (int bytes = 0; bytes < totalBytes; bytes++) {
      byte[] bb = new byte[bytes];

  @GwtIncompatible // different overflow behavior; could probably be made to work by using ~~
  public void testConcat_overflow_nonNegative() {
    int dim1 = 1 << 16;
    int dim2 = 1 << 16;
    assertThat(dim1 * dim2).isAtLeast(0);
    testConcatOverflow(dim1, dim2);
  }

  private static void testConcatOverflow(int arraysDim1, int arraysDim2) {
    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    byte[] mutated = hash.asBytes();
    mutated[0]++;
    assertThat(hash.asBytes()).isEqualTo(original);
  }

  private static void assertReadableBytes(HashCode hashCode) {
    assertThat(hashCode.bits()).isAtLeast(32); // sanity
    byte[] hashBytes = hashCode.asBytes();
    int totalBytes = hashCode.bits() / 8;

    for (int bytes = 0; bytes < totalBytes; bytes++) {
      byte[] bb = new byte[bytes];