def test_noResponse(self):
     """
     When there is no response set, calling C{checkPassword} will return
     L{False}.
     """
     c = CramMD5Credentials()
     self.assertFalse(c.checkPassword(b'secret'))
 def test_idempotentChallenge(self):
     """
     The same L{CramMD5Credentials} will always provide the same challenge,
     no matter how many times it is called.
     """
     c = CramMD5Credentials()
     chal = c.getChallenge()
     self.assertEqual(chal, c.getChallenge())
 def test_checkPassword(self):
     """
     When a valid response (which is a hex digest of the challenge that has
     been encrypted by the user's shared secret) is set on the
     L{CramMD5Credentials} that created the challenge, and C{checkPassword}
     is called with the user's shared secret, it will return L{True}.
     """
     c = CramMD5Credentials()
     chal = c.getChallenge()
     c.response = hexlify(HMAC(b"secret", chal, digestmod=hashlib.md5).digest())
     self.assertTrue(c.checkPassword(b"secret"))
 def test_wrongPassword(self):
     """
     When an invalid response is set on the L{CramMD5Credentials} (one that
     is not the hex digest of the challenge, encrypted with the user's shared
     secret) and C{checkPassword} is called with the user's correct shared
     secret, it will return L{False}.
     """
     c = CramMD5Credentials()
     chal = c.getChallenge()
     c.response = hexlify(HMAC(b'thewrongsecret', chal).digest())
     self.assertFalse(c.checkPassword(b'secret'))
 def test_setResponse(self):
     """
     When C{setResponse} is called with a string that is the username and
     the hashed challenge separated with a space, they will be set on the
     L{CramMD5Credentials}.
     """
     c = CramMD5Credentials()
     chal = c.getChallenge()
     c.setResponse(b" ".join(
         (b"squirrel", hexlify(HMAC(b'supersecret', chal).digest()))))
     self.assertTrue(c.checkPassword(b'supersecret'))
     self.assertEqual(c.username, b"squirrel")