test/test_rand.py

# Copyright (C) Frederick Dean 2009, All rights reserved

"""
Unit tests for L{OpenSSL.rand}.
"""

from unittest import main
import os 
import stat

from OpenSSL.test.util import TestCase
from OpenSSL import rand

class RandTests(TestCase):
    def test_bytes(self):
        """
        Verify that we can obtain bytes from rand_bytes() and
        that they are different each time.  Test the parameter
        of rand_bytes() for bad values.
        """
        b1 = rand.bytes(50)
        self.assertEqual(len(b1), 50)
        b2 = rand.bytes(num_bytes=50)  # parameter by name
        self.assertNotEqual(b1, b2)  #  Hip, Hip, Horay! FIPS complaince
        b3 = rand.bytes(num_bytes=0) 
        self.assertEqual(len(b3), 0)
        try:
            b4 = rand.bytes(-1) 
            self.assertTrue(False)  # We shouldn't get here
        except ValueError, v:
            self.assertTrue(v.message == "num_bytes must not be negative")


    def test_add(self):
        """
        Test adding of entropy to the PRNG.
        """
        rand.add('hamburger', 3)
        rand.seed('milk shake')
        self.assertTrue(rand.status())


    def test_files(self):
        """
        Test reading and writing of files via rand functions.
        """
        # Write random bytes to a file 
        tmpfile = self.mktemp()
        rand.write_file(tmpfile)
        # Verify length of written file
        size = os.stat(tmpfile)[stat.ST_SIZE]
        self.assertEquals(size, 1024)
        # Read random bytes from file 
        rand.load_file(tmpfile)
        rand.load_file(tmpfile, 4)  # specify a length
        # Cleanup
        os.unlink(tmpfile)


if __name__ == '__main__':
    main()