tests/test_blocks.py

'''Tests block operations.'''

from StringIO import StringIO
import unittest

import rsa
from rsa import blocks

class VarintTest(unittest.TestCase):

    def test_read_varint(self):
        
        encoded = '\xac\x02crummy'
        infile = StringIO(encoded)

        (decoded, read) = blocks.read_varint(infile)

        # Test the returned values
        self.assertEqual(300, decoded)
        self.assertEqual(2, read)

        # The rest of the file should be untouched
        self.assertEqual('crummy', infile.read())

    def test_read_zero(self):
        
        encoded = '\x00crummy'
        infile = StringIO(encoded)

        (decoded, read) = blocks.read_varint(infile)

        # Test the returned values
        self.assertEqual(0, decoded)
        self.assertEqual(1, read)

        # The rest of the file should be untouched
        self.assertEqual('crummy', infile.read())

    def test_write_varint(self):
        
        expected = '\xac\x02'
        outfile = StringIO()

        written = blocks.write_varint(outfile, 300)

        # Test the returned values
        self.assertEqual(expected, outfile.getvalue())
        self.assertEqual(2, written)


    def test_write_zero(self):
        
        outfile = StringIO()
        written = blocks.write_varint(outfile, 0)

        # Test the returned values
        self.assertEqual('\x00', outfile.getvalue())
        self.assertEqual(1, written)


class VarblockTest(unittest.TestCase):

    def test_yield_varblock(self):
        infile = StringIO('\x01\x0512345\x06Sybren')

        varblocks = list(blocks.yield_varblocks(infile))
        self.assertEqual(['12345', 'Sybren'], varblocks)

class FixedblockTest(unittest.TestCase):

    def test_yield_fixedblock(self):

        infile = StringIO('123456Sybren')

        fixedblocks = list(blocks.yield_fixedblocks(infile, 6))
        self.assertEqual(['123456', 'Sybren'], fixedblocks)

class BigfileTest(unittest.TestCase):

    def test_encrypt_decrypt_bigfile(self):

        # Expected block size + 11 bytes padding
        pub_key, priv_key = rsa.newkeys((6 + 11) * 8)

        # Encrypt the file
        message = '123456Sybren'
        infile = StringIO(message)
        outfile = StringIO()

        blocks.encrypt_bigfile(infile, outfile, pub_key)

        # Test
        crypto = outfile.getvalue()

        cryptfile = StringIO(crypto)
        clearfile = StringIO()

        blocks.decrypt_bigfile(cryptfile, clearfile, priv_key)
        self.assertEquals(clearfile.getvalue(), message)
        
        # We have 2x6 bytes in the message, so that should result in two
        # blocks.
        cryptfile.seek(0)
        varblocks = list(blocks.yield_varblocks(cryptfile))
        self.assertEqual(2, len(varblocks))