vcsserver/tests/test_subprocessio.py

# RhodeCode VCSServer provides access to different vcs backends via network.
# Copyright (C) 2014-2020 RhodeCode GmbH
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA

import io
import os
import sys

import pytest

from vcsserver import subprocessio
from vcsserver.str_utils import ascii_bytes


class FileLikeObj(object):  # pragma: no cover

    def __init__(self, data: bytes, size):
        chunks = size // len(data)

        self.stream = self._get_stream(data, chunks)

    def _get_stream(self, data, chunks):
        for x in range(chunks):
            yield data

    def read(self, n):

        buffer_stream = b''
        for chunk in self.stream:
            buffer_stream += chunk
            if len(buffer_stream) >= n:
                break

        # self.stream = self.bytes[n:]
        return buffer_stream


@pytest.fixture(scope='module')
def environ():
    """Delete coverage variables, as they make the tests fail."""
    env = dict(os.environ)
    for key in list(env.keys()):
        if key.startswith('COV_CORE_'):
            del env[key]

    return env


def _get_python_args(script):
    return [sys.executable, '-c', 'import sys; import time; import shutil; ' + script]


def test_raise_exception_on_non_zero_return_code(environ):
    call_args = _get_python_args('raise ValueError("fail")')
    with pytest.raises(OSError):
        b''.join(subprocessio.SubprocessIOChunker(call_args, shell=False, env=environ))


def test_does_not_fail_on_non_zero_return_code(environ):
    call_args = _get_python_args('sys.stdout.write("hello"); sys.exit(1)')
    proc = subprocessio.SubprocessIOChunker(call_args, shell=False, fail_on_return_code=False, env=environ)
    output = b''.join(proc)

    assert output == b'hello'


def test_raise_exception_on_stderr(environ):
    call_args = _get_python_args('sys.stderr.write("WRITE_TO_STDERR"); time.sleep(1);')

    with pytest.raises(OSError) as excinfo:
        b''.join(subprocessio.SubprocessIOChunker(call_args, shell=False, env=environ))

    assert 'exited due to an error:\nWRITE_TO_STDERR' in str(excinfo.value)


def test_does_not_fail_on_stderr(environ):
    call_args = _get_python_args('sys.stderr.write("WRITE_TO_STDERR"); sys.stderr.flush; time.sleep(2);')
    proc = subprocessio.SubprocessIOChunker(call_args, shell=False, fail_on_stderr=False, env=environ)
    output = b''.join(proc)

    assert output == b''


@pytest.mark.parametrize('size', [
    1,
    10 ** 5
])
def test_output_with_no_input(size, environ):
    call_args = _get_python_args(f'sys.stdout.write("X" * {size});')
    proc = subprocessio.SubprocessIOChunker(call_args, shell=False, env=environ)
    output = b''.join(proc)

    assert output == ascii_bytes("X" * size)


@pytest.mark.parametrize('size', [
    1,
    10 ** 5
])
def test_output_with_no_input_does_not_fail(size, environ):

    call_args = _get_python_args(f'sys.stdout.write("X" * {size}); sys.exit(1)')
    proc = subprocessio.SubprocessIOChunker(call_args, shell=False, fail_on_return_code=False, env=environ)
    output = b''.join(proc)

    assert output == ascii_bytes("X" * size)


@pytest.mark.parametrize('size', [
    1,
    10 ** 5
])
def test_output_with_input(size, environ):
    data_len = size
    inputstream = FileLikeObj(b'X', size)

    # This acts like the cat command.
    call_args = _get_python_args('shutil.copyfileobj(sys.stdin, sys.stdout)')
    # note: in this tests we explicitly don't assign chunker to a variable and let it stream directly
    output = b''.join(
        subprocessio.SubprocessIOChunker(call_args, shell=False, input_stream=inputstream, env=environ)
    )

    assert len(output) == data_len


@pytest.mark.parametrize('size', [
    1,
    10 ** 5
])
def test_output_with_input_skipping_iterator(size, environ):
    data_len = size
    inputstream = FileLikeObj(b'X', size)

    # This acts like the cat command.
    call_args = _get_python_args('shutil.copyfileobj(sys.stdin, sys.stdout)')

    # Note: assigning the chunker makes sure that it is not deleted too early
    proc = subprocessio.SubprocessIOChunker(call_args, shell=False, input_stream=inputstream, env=environ)
    output = b''.join(proc.stdout)

    assert len(output) == data_len