tests/test_bifid.py

   1 import pytest
   2 import string
   3
   4 from szyfrow.bifid import *
   5 from szyfrow.support.utilities import *
   6
   7 def test_grid():
   8     trans, f_grid, r_grid = bifid_grid('bayes', KeywordWrapAlphabet.from_a, None)
   9     assert len(f_grid) == 25
  10     assert len(r_grid) == 25
  11     for l in f_grid:
  12         assert l == r_grid[f_grid[l]]
  13     assert r_grid[1, 1] == 'b'
  14     assert r_grid[2, 1] == 'c'
  15
  16
  17 def test_encipher_message():
  18     assert bifid_encipher("indiajelly", 'iguana') == 'ibidonhprm'
  19     assert bifid_encipher("indiacurry", 'iguana', period=4, fillvalue='x') == 'ibnhgaqltzml'
  20     with pytest.raises(ValueError):
  21         bifid_encipher("indiacurry", 'iguana', period=4)
  22
  23
  24 def test_decipher_message():
  25     plaintext = 'hereissometexttoencipher'
  26     for key in ['bayes', 'samplekey']:
  27         enciphered = bifid_encipher(plaintext, key)
  28         deciphered = bifid_decipher(enciphered, key)
  29         assert deciphered == plaintext
  30
  31     for key in ['bayes', 'samplekey']:
  32         enciphered = bifid_encipher(plaintext, key, period=5, fillvalue='a')
  33         deciphered = bifid_decipher(enciphered, key, period=5, fillvalue='a')
  34         assert deciphered == plaintext + pad(len(plaintext), 5, 'a')
  35
  36
  37 def test_bifid_break():
  38     plaintext = sanitise('''It is a truth universally acknowledged, that a single man in
  39              possession of a good fortune, must be in want of a wife. However
  40              little known the feelings or views of such a man may be on his
  41              first entering a neighbourhood, this truth is so well fixed in
  42              the minds of the surrounding families, that he is considered the
  43              rightful property of some one or other of their daughters.''')
  44     expected_key = 'encipher'
  45     expected_wrap = KeywordWrapAlphabet.from_a
  46     expected_period = 0
  47     expected_score = Pletters(plaintext)
  48     ciphertext = bifid_encipher(plaintext, expected_key,
  49         wrap_alphabet=expected_wrap)
  50
  51     (key, wrap, period), score = bifid_break(ciphertext,
  52         wordlist='encipher fourteen keyword'.split())
  53
  54     assert key == expected_key
  55     assert wrap == expected_wrap
  56     assert period == expected_period
  57     assert score == pytest.approx(expected_score)