tests/test_amsco.py

   1 import pytest
   2 import string
   3
   4 from szyfrow.amsco import *
   5 from szyfrow.support.utilities import *
   6 from szyfrow.support.language_models import transpositions_of
   7
   8 def test_positions():
   9     grid = amsco_positions(string.ascii_lowercase, 'freddy', fillpattern=(1, 2))
  10     assert grid == [[AmscoSlice(index=3, start=4, end=6),
  11      AmscoSlice(index=2, start=3, end=4),
  12      AmscoSlice(index=0, start=0, end=1),
  13      AmscoSlice(index=1, start=1, end=3),
  14      AmscoSlice(index=4, start=6, end=7)],
  15     [AmscoSlice(index=8, start=12, end=13),
  16      AmscoSlice(index=7, start=10, end=12),
  17      AmscoSlice(index=5, start=7, end=9),
  18      AmscoSlice(index=6, start=9, end=10),
  19      AmscoSlice(index=9, start=13, end=15)],
  20     [AmscoSlice(index=13, start=19, end=21),
  21      AmscoSlice(index=12, start=18, end=19),
  22      AmscoSlice(index=10, start=15, end=16),
  23      AmscoSlice(index=11, start=16, end=18),
  24      AmscoSlice(index=14, start=21, end=22)],
  25     [AmscoSlice(index=18, start=27, end=28),
  26      AmscoSlice(index=17, start=25, end=27),
  27      AmscoSlice(index=15, start=22, end=24),
  28      AmscoSlice(index=16, start=24, end=25),
  29      AmscoSlice(index=19, start=28, end=30)]]
  30
  31 def test_encipher_message():
  32     ciphertext = amsco_encipher('hellothere', 'abc', fillpattern=(1, 2))
  33     assert ciphertext == 'hoteelhler'
  34
  35     ciphertext = amsco_encipher('hellothere', 'abc', fillpattern=(2, 1))
  36     assert ciphertext == 'hetelhelor'
  37
  38     ciphertext = amsco_encipher('hellothere', 'acb', fillpattern=(1, 2))
  39     assert ciphertext == 'hotelerelh'
  40
  41     ciphertext = amsco_encipher('hellothere', 'acb', fillpattern=(2, 1))
  42     assert ciphertext == 'hetelorlhe'
  43
  44     ciphertext = amsco_encipher('hereissometexttoencipher', 'encode')
  45     assert ciphertext == 'etecstthhomoerereenisxip'
  46
  47     ciphertext = amsco_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 2))
  48     assert ciphertext == 'hetcsoeisterereipexthomn'
  49
  50     ciphertext = amsco_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 2), fillstyle=AmscoFillStyle.continuous)
  51     assert ciphertext == 'hecsoisttererteipexhomen'
  52
  53     ciphertext = amsco_encipher('hereissometexttoencipher', 'cipher', fillpattern=(2, 1))
  54     assert ciphertext == 'heecisoosttrrtepeixhemen'
  55
  56     ciphertext = amsco_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 3, 2))
  57     assert ciphertext == 'hxtomephescieretoeisnter'
  58
  59     ciphertext = amsco_encipher('hereissometexttoencipher', 'cipher', fillpattern=(1, 3, 2), fillstyle=AmscoFillStyle.continuous)
  60     assert ciphertext == 'hxomeiphscerettoisenteer'
  61
  62
  63 def test_decipher_message():
  64     plaintext = 'hereissometexttoencipher'
  65     for key in ['bayes', 'samplekey']:
  66         for fillpattern in [(1, 2), (2, 1)]:
  67             for fillstyle in AmscoFillStyle:
  68                 enciphered = amsco_encipher(plaintext, key,
  69                     fillpattern=fillpattern, fillstyle=fillstyle)
  70                 deciphered = amsco_decipher(enciphered, key,
  71                     fillpattern=fillpattern, fillstyle=fillstyle)
  72                 assert deciphered == plaintext
  73
  74
  75 def test_amsco_break():
  76     plaintext = sanitise('''It is a truth universally acknowledged, that a single man in
  77              possession of a good fortune, must be in want of a wife. However
  78              little known the feelings or views of such a man may be on his
  79              first entering a neighbourhood, this truth is so well fixed in
  80              the minds of the surrounding families, that he is considered the
  81              rightful property of some one or other of their daughters.''')
  82     expected_key = 'encipher'
  83     expected_fillpattern = (1, 2)
  84     expected_fillsytle = AmscoFillStyle.continuous
  85     expected_score = Pbigrams(plaintext)
  86     ciphertext = amsco_encipher(plaintext, expected_key,
  87         fillpattern=expected_fillpattern, fillstyle=expected_fillsytle)
  88     used_translist = collections.defaultdict(list)
  89     for word in 'encipher fourteen keyword'.split():
  90         used_translist[transpositions_of(word)] += [word]
  91
  92     (key, fillpattern, fillstyle), score = amsco_break(ciphertext,
  93         translist=used_translist)
  94
  95     assert key == transpositions_of(expected_key)
  96     assert fillpattern == expected_fillpattern
  97     assert fillstyle == expected_fillsytle
  98     assert score == pytest.approx(expected_score)