assertEquals(hashFunction.hashBytes(bytes), hashFunction.hashBytes(ByteBuffer.wrap(bytes)));
  }

  static void assertHashByteBufferExhaustsBuffer(HashFunction hashFunction) {
    Random rng = new Random(0L);
    byte[] bytes = new byte[rng.nextInt(256) + 1];
    rng.nextBytes(bytes);
    ByteBuffer buffer = ByteBuffer.wrap(bytes);
    HashCode unused = hashFunction.hashBytes(buffer);

      buffer.putChar(input.charAt(i));
    }
    return hashBytes(buffer.array());
  }

  @Override
  public HashCode hashString(CharSequence input, Charset charset) {
    return hashBytes(input.toString().getBytes(charset));
  }

  @Override
  public abstract HashCode hashBytes(byte[] input, int off, int len);

  @Override
  public HashCode hashBytes(ByteBuffer input) {

    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;
  }

  @Benchmark
  int hashFunctionWithOffset(int reps) {
    HashFunction hashFunction = hashFunctionEnum.getHashFunction();
    int result = 37;
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes, 1, testBytes.length - 1).asBytes()[0];
    }
    return result;

    assertEquals(hashFunction.hashBytes(bytes), hashFunction.hashBytes(ByteBuffer.wrap(bytes)));
  }

  static void assertHashByteBufferExhaustsBuffer(HashFunction hashFunction) {
    Random rng = new Random(0L);
    byte[] bytes = new byte[rng.nextInt(256) + 1];
    rng.nextBytes(bytes);
    ByteBuffer buffer = ByteBuffer.wrap(bytes);
    HashCode unused = hashFunction.hashBytes(buffer);

    Mac mac = Mac.getInstance(algorithm);
    mac.init(key);
    mac.update(input);

    assertEquals(HashCode.fromBytes(mac.doFinal()), hashFunc.hashBytes(input));
    assertEquals(HashCode.fromBytes(mac.doFinal(input)), hashFunc.hashBytes(input));
  }

  // Tests from RFC2022: https://tools.ietf.org/html/rfc2202

  public void testRfc2202_hmacSha1_case1() {
    byte[] key = fillByteArray(20, 0x0b);

	}
	if int64(len(p)) > b.shardSize {
		return 0, errors.New("unexpected bitrot buffer size")
	}
	if int64(len(p)) < b.shardSize {
		b.finished = true
	}
	b.h.Reset()
	b.h.Write(p)
	hashBytes := b.h.Sum(nil)
	_, err := b.iow.Write(hashBytes)
	if err != nil {
		b.closeWithErr(err)
		return 0, err
	}
	n, err := b.iow.Write(p)
	if err != nil {
		b.closeWithErr(err)
		return n, err
	}
	if n != len(p) {

    verify(hashFunction).newHasher();
    verifyNoMoreInteractions(hashFunction, hasher);
  }

  public void testHash_hashesCorrectly() throws Exception {
    HashCode expectedHash = Hashing.md5().hashBytes(testBytes);
    HashingInputStream in = new HashingInputStream(Hashing.md5(), buffer);

    byte[] buf = new byte[4];
    int numOfByteRead = in.read(buf, 0, buf.length);
    assertEquals(4, numOfByteRead);

    Mac mac = Mac.getInstance(algorithm);
    mac.init(key);
    mac.update(input);

    assertEquals(HashCode.fromBytes(mac.doFinal()), hashFunc.hashBytes(input));
    assertEquals(HashCode.fromBytes(mac.doFinal(input)), hashFunc.hashBytes(input));
  }

  // Tests from RFC2022: https://tools.ietf.org/html/rfc2202

  public void testRfc2202_hmacSha1_case1() {
    byte[] key = fillByteArray(20, 0x0b);

        return md.digest();
      }
    },
    HASH_FUNCTION_DIRECT() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().hashBytes(input).asBytes();
      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {

        return md.digest();
      }
    },
    HASH_FUNCTION_DIRECT() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {
        return algorithm.getHashFunction().hashBytes(input).asBytes();
      }
    },
    HASH_FUNCTION_VIA_HASHER() {
      @Override
      public byte[] hash(Algorithm algorithm, byte[] input) {