gpgme/lang/python/tests/t-idiomatic.py

#!/usr/bin/env python3

# Copyright (C) 2016 g10 Code GmbH
#
# This file is part of GPGME.
#
# GPGME is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# GPGME is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
# Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this program; if not, see <http://www.gnu.org/licenses/>.

import io
import os
import tempfile
from pyme import core, constants, errors
import support

support.init_gpgme(constants.PROTOCOL_OpenPGP)

# Both Context and Data can be used as context manager:
with core.Context() as c, core.Data() as d:
    c.get_engine_info()
    d.write(b"Halloechen")
    leak_c = c
    leak_d = d
assert leak_c.wrapped == None
assert leak_d.wrapped == None

def sign_and_verify(source, signed, sink):
    with core.Context() as c:
        c.op_sign(source, signed, constants.SIG_MODE_NORMAL)
        signed.seek(0, os.SEEK_SET)
        c.op_verify(signed, None, sink)
        result = c.op_verify_result()

    assert len(result.signatures) == 1, "Unexpected number of signatures"
    sig = result.signatures[0]
    assert sig.summary == 0
    assert errors.GPGMEError(sig.status).getcode() == errors.NO_ERROR

    sink.seek(0, os.SEEK_SET)
    assert sink.read() == b"Hallo Leute\n"

# Demonstrate automatic wrapping of file-like objects with 'fileno'
# method.
with tempfile.TemporaryFile() as source, \
     tempfile.TemporaryFile() as signed, \
     tempfile.TemporaryFile() as sink:
    source.write(b"Hallo Leute\n")
    source.seek(0, os.SEEK_SET)

    sign_and_verify(source, signed, sink)

# XXX: Python's io.BytesIo.truncate does not work as advertised.
# http://bugs.python.org/issue27261
bio = io.BytesIO()
bio.truncate(1)
if len(bio.getvalue()) != 1:
    # This version of Python is affected, preallocate buffer.
    preallocate = 128*b'\x00'
else:
    preallocate = b''

# Demonstrate automatic wrapping of objects implementing the buffer
# interface, and the use of data objects with the 'with' statement.
with io.BytesIO(preallocate) as signed, core.Data() as sink:
    sign_and_verify(b"Hallo Leute\n", signed, sink)