bf.put(-1);
    for (int i = 0; i < numInsertions; i++) {
      bf.put(i);
    }
    assertApproximateElementCountGuess(bf, numInsertions);
  }

  public void testEquals_empty() {
    new EqualsTester()
        .addEqualityGroup(BloomFilter.create(byteArrayFunnel(), 100, 0.01))
        .addEqualityGroup(BloomFilter.create(byteArrayFunnel(), 100, 0.02))