#!/usr/bin/env python3
##############################################################################
#
# Copyright (C) Gennady Trafimenkov, 2010
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
from crc16 import _crc16
from crc16 import crc16pure
import crc16
import unittest
class TestCRC16XModem(unittest.TestCase):
"""Test CRC16 CRC-CCITT (XModem) variant.
"""
def doBasics(self, module):
"""Test basic functionality.
"""
# very basic example
self.assertEqual(module.crc16xmodem(b'123456789'), 0x31c3)
self.assertNotEqual(module.crc16xmodem(b'123456'), 0x31c3)
# the same in two steps
crc = module.crc16xmodem(b'12345')
crc = module.crc16xmodem(b'6789', crc)
self.assertEqual(crc, 0x31C3)
# more basic checks
self.assertEqual(module.crc16xmodem(b'AAAAAAAAAAAAAAAAAAAAAA'), 0x92cd)
# bigger chunks
self.assertEqual(module.crc16xmodem(b'A' * 4096), 0xd694)
self.assertEqual(module.crc16xmodem(b'A' * 39999), 0xcfbb)
# test when there are no data
self.assertEqual(module.crc16xmodem(b''), 0)
def test_basics(self):
"""Test basic functionality.
"""
self.doBasics(crc16)
def test_basics_c(self):
"""Test basic functionality of the extension module.
"""
self.doBasics(_crc16)
def test_basics_pure(self):
"""Test basic functionality of the pure module.
"""
self.doBasics(crc16pure)
def test_big_chunks(self):
"""Test calculation of CRC on big chunks of data.
Test only the extension module becase the pure one will work very long for these tests.
"""
self.assertEqual(_crc16.crc16xmodem(b'A' * 16 * 1024 * 1024), 0xbf75)
if __name__ == '__main__':
unittest.main()
