new_contents: import pytest
  
  
  def _call_extend(crc, chunk):
      import crc32c
      return crc32c.extend(crc, chunk, len(chunk))
  
  
  def test_extend_w_empty_chunk():
      assert _call_extend(123, b'') == 123
  
  
  # From: https://tools.ietf.org/html/rfc3720#appendix-B.4
  iscsi_scsi_read_10_command_pdu = [
      0x01, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00,
      0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x18, 0x28, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  ]
  
  _EXPECTED = [
      (b'', 0x00000000),
      (b'\x00' * 32, 0x8a9136aa),
      (b'\xff' * 32, 0x62a8ab43),
      (bytes(range(32)), 0x46dd794e),
      (bytes(reversed(range(32))), 0x113fdb5c),
      (bytes(iscsi_scsi_read_10_command_pdu), 0xd9963a56),
  ]
  
  
  def _call_value(chunk):
      import crc32c
      return crc32c.value(chunk, len(chunk))
  
  
  @pytest.mark.parametrize("chunk, expected", _EXPECTED)
  def test_value(chunk, expected):
      assert _call_value(chunk) == expected
  
subject: Add tests derived from RFC 3720, section B.4.