PySecretHandshake/secret_handshake/test_boxstream.py

# Copyright (c) 2017 PySecretHandshake contributors (see AUTHORS for more details)
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import pytest
from io import BytesIO

from .test_crypto import (CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
from secret_handshake.boxstream import BoxStream, UnboxStream, HEADER_LENGTH

MESSAGE_1 = (b'\xcev\xedE\x06l\x02\x13\xc8\x17V\xfa\x8bZ?\x88B%O\xb0L\x9f\x8e\x8c0y\x1dv\xc0\xc9\xf6\x9d\xc2\xdf\xdb'
             b'\xee\x9d')
MESSAGE_2 = b"\x141\xd63\x13d\xd1\xecZ\x9b\xd0\xd4\x03\xcdR?'\xaa.\x89I\x92I\xf9guL\xaa\x06?\xea\xca/}\x88*\xb2"
MESSAGE_3 = (b'\xcbYY\xf1\x0f\xa5O\x13r\xa6"\x15\xc5\x9d\r.*\x0b\x92\x10m\xa6(\x0c\x0c\xc61\x80j\x81)\x800\xed\xda'
             b'\xad\xa1')
MESSAGE_CLOSED = b'\xb1\x14hU\'\xb5M\xa6"\x03\x9duy\xa1\xd4evW,\xdcE\x18\xe4+ C4\xe8h\x96\xed\xc5\x94\x80'


class AsyncBuffer(BytesIO):
    """Just a BytesIO with an async read method."""
    async def read(self, n=None):
        return super(AsyncBuffer, self).read(n)
    readexactly = read


@pytest.mark.asyncio
async def test_boxstream():
    buffer = AsyncBuffer()
    box_stream = BoxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
    box_stream.write(b'foo')
    buffer.seek(0)
    assert await buffer.read() == MESSAGE_1

    pos = buffer.tell()
    box_stream.write(b'foo')
    buffer.seek(pos)
    assert await buffer.read() == MESSAGE_2

    pos = buffer.tell()
    box_stream.write(b'bar')
    buffer.seek(pos)
    assert await buffer.read() == MESSAGE_3

    pos = buffer.tell()
    box_stream.close()
    buffer.seek(pos)
    assert await buffer.read() == MESSAGE_CLOSED


@pytest.mark.asyncio
async def test_unboxstream():
    buffer = AsyncBuffer(MESSAGE_1 + MESSAGE_2 + MESSAGE_3 + MESSAGE_CLOSED)
    buffer.seek(0)

    unbox_stream = UnboxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
    assert not unbox_stream.closed
    assert [msg async for msg in unbox_stream] == [b'foo', b'foo', b'bar']
    assert unbox_stream.closed


@pytest.mark.asyncio
async def test_long_packets():
    data_size = 6 * 1024
    data = bytes(n % 256 for n in range(data_size))

    # box 6K buffer
    buffer = AsyncBuffer()
    box_stream = BoxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
    box_stream.write(data)
    # the size overhead corresponds to the two packet headers
    assert buffer.tell() == data_size + (HEADER_LENGTH * 2)
    buffer.seek(0)

    # now let's unbox it and check whether it's OK
    unbox_stream = UnboxStream(buffer, CLIENT_ENCRYPT_KEY, CLIENT_ENCRYPT_NONCE)
    first_packet = await unbox_stream.read()
    assert first_packet == data[:4096]
    second_packet = await unbox_stream.read()
    assert second_packet == data[4096:]