tests/test_polybius.py

   1 import pytest
   2 import string
   3
   4 from szyfrow.polybius import *
   5 from szyfrow.support.utilities import *
   6
   7 def test_grid():
   8     grid = polybius_grid('a', 'abcde', 'abcde')
   9     assert grid['x'] == ('e', 'c')
  10     grid = polybius_grid('elephant', 'abcde', 'abcde')
  11     assert grid['e'] == ('a', 'a')
  12     assert grid['b'] == ('b', 'c')
  13
  14 def test_reverse_grid():
  15     grid = polybius_reverse_grid('a', 'abcde', 'abcde')
  16     assert grid['e', 'c'] == 'x'
  17     grid = polybius_reverse_grid('elephant', 'abcde', 'abcde')
  18     assert grid['a', 'a'] == 'e'
  19     assert grid['b', 'c'] == 'b'
  20
  21 def test_grid_round_trip():
  22     ltm = {'j': 'i'}
  23     fgrid = polybius_grid('elephant', 'abcde', 'abcde',
  24         letters_to_merge=ltm)
  25     rgrid = polybius_reverse_grid('elephant', 'abcde', 'abcde',
  26         letters_to_merge=ltm)
  27     for l in fgrid:
  28         if l in ltm:
  29             assert ltm[l] == rgrid[fgrid[l]]
  30         else:
  31             assert l == rgrid[fgrid[l]]
  32     for p in rgrid:
  33         assert p == fgrid[rgrid[p]]
  34
  35
  36 def test_polybius_flatten():
  37     assert polybius_flatten(('a', 'b'), column_first=True) == 'ba'
  38     assert polybius_flatten(('a', 'b'), column_first=False) == 'ab'
  39
  40
  41 def test_encipher_message():
  42     ct = polybius_encipher('this is a test message for the ' \
  43           'polybius decipherment', 'elephant', \
  44           [1, 2, 3, 4, 5], [1, 2, 3, 4, 5], \
  45           wrap_alphabet=KeywordWrapAlphabet.from_last)
  46     assert ct == '2214445544551522115522511155551543114252542214111352123234442355411135441314115451112122'
  47
  48     ct = polybius_encipher('this is a test message for the ' \
  49           'polybius decipherment', 'elephant', 'abcde', 'abcde', \
  50           column_first=False)
  51     assert ct == 'bbadccddccddaebbaaddbbceaaddddaecbaacadadcbbadaaacdaabedbcccdeddbeaabdccacadaadcceaababb'
  52
  53     ct = polybius_encipher('this is a test message for the ' \
  54           'polybius decipherment', 'elephant', 'abcde', 'abcde', \
  55           column_first=True)
  56     assert ct == 'bbdaccddccddeabbaaddbbecaaddddeabcaaacadcdbbdaaacaadbadecbccedddebaadbcccadaaacdecaaabbb'
  57
  58
  59 def test_decipher_message():
  60     plaintext = sanitise('''Whoever has made a voyage up the Hudson must
  61         remember the Kaatskill mountains. They are a dismembered branch of
  62         the great''')
  63     for key in ['wink', 'elephant', 'swashbuckling']:
  64         enciphered = polybius_encipher(plaintext, key, 'abcde', 'abcde')
  65         deciphered = polybius_decipher(enciphered, key, 'abcde', 'abcde')
  66         assert deciphered == plaintext
  67
  68
  69 def test_cadenus_break():
  70     plaintext = sanitise('''You will rejoice to hear that no disaster has accompanied the
  71         commencement of an enterprise which you have regarded with such evil
  72         forebodings.  I arrived here yesterday, and my first task is to assure
  73         my dear sister of my welfare and increasing confidence in the success
  74         of my undertaking.''')
  75     expected_key = 'swashbuckling'
  76     expected_wrap = KeywordWrapAlphabet.from_last
  77     expected_row_order = 'abcde'
  78     expected_col_order = 'abcde'
  79     expected_col_first = True
  80     ciphertext = polybius_encipher(plaintext, expected_key,
  81         expected_col_order, expected_row_order,
  82         column_first=expected_col_first, wrap_alphabet=expected_wrap)
  83
  84     trans_table = ''.maketrans('j', 'i')
  85     expected_score = Ptrigrams(plaintext.translate(trans_table))
  86
  87     dictionary = ['clearinghouse', 'computerising', 'counterclaims',
  88         'housewarmings',  'intravenously', 'liquefactions', 'somersaulting',
  89         'sportsmanlike', 'swashbuckling']
  90
  91     # dictionary = ['swashbuckling']
  92
  93     (key, wrap, col_order, row_order, col_first), score = polybius_break(ciphertext,
  94         expected_col_order, expected_row_order,
  95         wordlist=dictionary, fitness=Ptrigrams)
  96
  97     assert key == expected_key
  98     assert wrap == expected_wrap
  99     assert col_first == expected_col_first
 100     assert score == pytest.approx(expected_score)