for (int n = 1; n < 1000; n++) {
      for (int m = 0; m < 1000; m++) {
        assertTrue(BloomFilter.optimalNumOfHashFunctions(n, m) > 0);
      }
    }
  }

  // https://github.com/google/guava/issues/1781
  public void testOptimalNumOfHashFunctionsRounding() {
    assertEquals(7, BloomFilter.optimalNumOfHashFunctions(319, 3072));
  }

  /** Tests that we always get a non-negative optimal size. */

     * optimalM(1000, 0.0000000000000001) = 76680 which is less than 10kb. Who cares!
     */
    long numBits = optimalNumOfBits(expectedInsertions, fpp);
    int numHashFunctions = optimalNumOfHashFunctions(expectedInsertions, numBits);
    try {
      return new BloomFilter<>(new LockFreeBitArray(numBits), numHashFunctions, funnel, strategy);
    } catch (IllegalArgumentException e) {