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pysim
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add unit tests for BER-TLV encoder/decoder functions 

... and while at it resolve a bug in bertlv_parse_len()
discovered by those new tests.

Change-Id: I9f14dafab4f712c29224c4eb25cacab7885e2b68
This commit is contained in:
Harald Welte 2021-05-04 20:06:45 +02:00
parent c781ab85bc
commit de02718631
2 changed files with 25 additions and 1 deletions
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2
pySim/utils.py
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@ -132,7 +132,7 @@ def bertlv_parse_len(binary:bytes) -> Tuple[int, bytes]:
for i in range(1, 1+num_len_oct):
length <<= 8
length |= binary[i]
return (length, binary[num_len_oct:])
return (length, binary[1+num_len_oct:])
def bertlv_encode_len(length:int) -> bytes:
"""Encode a single Length value according to ITU-T X.690 8.1.3;

24
tests/test_utils.py
View File

@ -152,5 +152,29 @@ class DecTestCase(unittest.TestCase):
msisdn_decoded = utils.dec_msisdn("ffffffffffffffffffffffffffffffffffffffff0bb121436587092143658709ffff")
self.assertEqual(msisdn_decoded, (1, 3, "12345678901234567890"))
class TestBerTlv(unittest.TestCase):
def test_BerTlvTagDec(self):
res = utils.bertlv_parse_tag(b'\x01')
self.assertEqual(res, ({'tag':1, 'constructed':False, 'class': 0}, b''))
res = utils.bertlv_parse_tag(b'\x21')
self.assertEqual(res, ({'tag':1, 'constructed':True, 'class': 0}, b''))
res = utils.bertlv_parse_tag(b'\x81\x23')
self.assertEqual(res, ({'tag':1, 'constructed':False, 'class': 2}, b'\x23'))
res = utils.bertlv_parse_tag(b'\x1f\x8f\x00\x23')
self.assertEqual(res, ({'tag':0xf<<7, 'constructed':False, 'class': 0}, b'\x23'))
def test_BerTlvLenDec(self):
self.assertEqual(utils.bertlv_encode_len(1), b'\x01')
self.assertEqual(utils.bertlv_encode_len(127), b'\x7f')
self.assertEqual(utils.bertlv_encode_len(128), b'\x81\x80')
self.assertEqual(utils.bertlv_encode_len(0x123456), b'\x83\x12\x34\x56')
def test_BerTlvLenEnc(self):
self.assertEqual(utils.bertlv_parse_len(b'\x01\x23'), (1, b'\x23'))
self.assertEqual(utils.bertlv_parse_len(b'\x7f'), (127, b''))
self.assertEqual(utils.bertlv_parse_len(b'\x81\x80'), (128, b''))
self.assertEqual(utils.bertlv_parse_len(b'\x83\x12\x34\x56\x78'), (0x123456, b'\x78'))
if __name__ == "__main__":
unittest.main()