tests/test_railfence.py

   1 import pytest
   2 import string
   3
   4 from szyfrow.railfence import *
   5 from szyfrow.support.utilities import *
   6
   7
   8 def test_encipher_message():
   9     plaintext = 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers'
  10     ciphertext = railfence_encipher(plaintext, 2, fillvalue='!')
  11     expected = 'hlohraateerishsslnpeefetotsigaleccpeselteevsmhatetiiaogicotxfretnrifneihr!'
  12     assert ciphertext == expected
  13     ciphertext = railfence_encipher(plaintext, 3, fillvalue='!')
  14     expected = 'horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihr!!lhateihsnefttiaece!'
  15     assert ciphertext == expected
  16     ciphertext = railfence_encipher(plaintext, 5, fillvalue='!')
  17     expected = 'hresleogcseeemhetaocofrnrner!!lhateihsnefttiaece!!ltvsatiigitxetifih!!oarspeslp!'
  18     assert ciphertext == expected
  19     ciphertext = railfence_encipher(plaintext, 10, fillvalue='!')
  20     expected = 'hepisehagitnr!!lernesge!!lmtocerh!!otiletap!!tseaorii!!hassfolc!!evtitffe!!rahsetec!!eixn!'
  21     assert ciphertext == expected
  22     ciphertext = railfence_encipher(plaintext, 3)
  23     expected = 'horaersslpeeosglcpselteevsmhatetiiaogicotxfretnrifneihrlhateihsnefttiaece'
  24     assert ciphertext == expected
  25     ciphertext = railfence_encipher(plaintext, 5)
  26     expected = 'hresleogcseeemhetaocofrnrnerlhateihsnefttiaeceltvsatiigitxetifihoarspeslp'
  27     assert ciphertext == expected
  28     ciphertext = railfence_encipher(plaintext, 7)
  29     expected = 'haspolsevsetgifrifrlatihnettaeelemtiocxernhorersleesgcptehaiaottneihesfic'
  30     assert ciphertext == expected
  31
  32
  33 def test_decipher_message():
  34     plaintext = 'hellothereavastmeheartiesthisisalongpieceoftextfortestingrailfenceciphers'
  35     for key in range(2, 11):
  36         enciphered = railfence_encipher(plaintext, key)
  37         deciphered = railfence_decipher(enciphered, key)
  38         assert deciphered == plaintext
  39
  40
  41 def test_railfence_break():
  42     plaintext = sanitise('''It is a truth universally acknowledged, that a single man in
  43              possession of a good fortune, must be in want of a wife. However
  44              little known the feelings or views of such a man may be on his
  45              first entering a neighbourhood, this truth is so well fixed in
  46              the minds of the surrounding families, that he is considered the
  47              rightful property of some one or other of their daughters.''')
  48     expected_key = 7
  49     expected_score = Ptrigrams(plaintext)
  50     ciphertext = railfence_encipher(plaintext, expected_key)
  51
  52     key, score = railfence_break(ciphertext, fitness=Ptrigrams)
  53
  54     assert key == expected_key
  55     assert score == pytest.approx(expected_score)