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# fixtures: Fixtures with cleanups for testing and convenience.
#
# Copyright (c) 2010, 2011, Robert Collins <robertc@robertcollins.net>
#
# Licensed under either the Apache License, Version 2.0 or the BSD 3-clause
# license at the users choice. A copy of both licenses are available in the
# project source as Apache-2.0 and BSD. You may not use this file except in
# compliance with one of these two licences.
#
# Unless required by applicable law or agreed to in writing, software
# distributed under these licenses is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# license you chose for the specific language governing permissions and
# limitations under that license.
__all__ = [
'FakePopen',
'PopenFixture'
]
import random
import subprocess
import sys
from fixtures import Fixture
class FakeProcess(object):
"""A test double process, roughly meeting subprocess.Popen's contract."""
def __init__(self, args, info):
self._args = args
self.stdin = info.get('stdin')
self.stdout = info.get('stdout')
self.stderr = info.get('stderr')
self.pid = random.randint(0, 65536)
self._returncode = info.get('returncode', 0)
self.returncode = None
@property
def args(self):
return self._args["args"]
def poll(self):
"""Get the current value of FakeProcess.returncode.
The returncode is None before communicate() and/or wait() are called,
and it's set to the value provided by the 'info' dictionary otherwise
(or 0 in case 'info' doesn't specify a value).
"""
return self.returncode
def communicate(self, input=None, timeout=None):
self.returncode = self._returncode
if self.stdin and input:
self.stdin.write(input)
if self.stdout:
out = self.stdout.getvalue()
else:
out = ''
if self.stderr:
err = self.stderr.getvalue()
else:
err = ''
return out, err
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.wait()
def kill(self):
pass
def wait(self, timeout=None, endtime=None):
if self.returncode is None:
self.communicate()
return self.returncode
class FakePopen(Fixture):
"""Replace subprocess.Popen.
Primarily useful for testing, this fixture replaces subprocess.Popen with a
test double.
:ivar procs: A list of the processes created by the fixture.
"""
_unpassed = object()
def __init__(self, get_info=lambda _:{}):
"""Create a PopenFixture
:param get_info: Optional callback to control the behaviour of the
created process. This callback takes a kwargs dict for the Popen
call, and should return a dict with any desired attributes.
Only parameters that are supplied to the Popen call are in the
dict, making it possible to detect the difference between 'passed
with a default value' and 'not passed at all'.
e.g.
def get_info(proc_args):
self.assertEqual(subprocess.PIPE, proc_args['stdin'])
return {'stdin': StringIO('foobar')}
The default behaviour if no get_info is supplied is for the return
process to have returncode of None, empty streams and a random pid.
After communicate() or wait() are called on the process object,
the returncode is set to whatever get_info returns (or 0 if
get_info is not supplied or doesn't return a dict with an explicit
'returncode' key).
"""
super(FakePopen, self).__init__()
self.get_info = get_info
def _setUp(self):
self.addCleanup(setattr, subprocess, 'Popen', subprocess.Popen)
subprocess.Popen = self
self.procs = []
# The method has the correct signature so we error appropriately if called
# wrongly.
def __call__(self, args, bufsize=_unpassed, executable=_unpassed,
stdin=_unpassed, stdout=_unpassed, stderr=_unpassed,
preexec_fn=_unpassed, close_fds=_unpassed, shell=_unpassed,
cwd=_unpassed, env=_unpassed, universal_newlines=_unpassed,
startupinfo=_unpassed, creationflags=_unpassed,
restore_signals=_unpassed, start_new_session=_unpassed,
pass_fds=_unpassed, *, group=_unpassed, extra_groups=_unpassed,
user=_unpassed, umask=_unpassed, encoding=_unpassed,
errors=_unpassed, text=_unpassed, pipesize=_unpassed,
process_group=_unpassed):
# Reject arguments introduced by newer versions of Python in older
# versions; this makes it harder to accidentally hide compatibility
# problems using test doubles.
if sys.version_info < (3, 7) and text is not FakePopen._unpassed:
raise TypeError(
"FakePopen.__call__() got an unexpected keyword argument "
"'text'")
if sys.version_info < (3, 9):
for arg_name in "group", "extra_groups", "user", "umask":
if locals()[arg_name] is not FakePopen._unpassed:
raise TypeError(
"FakePopen.__call__() got an unexpected keyword "
"argument '{}'".format(arg_name))
if sys.version_info < (3, 10) and pipesize is not FakePopen._unpassed:
raise TypeError(
"FakePopen.__call__() got an unexpected keyword argument "
"'pipesize'")
if sys.version_info < (3, 11) and process_group is not FakePopen._unpassed:
raise TypeError(
"FakePopen.__call__() got an unexpected keyword argument "
"'process_group'")
proc_args = dict(args=args)
local = locals()
for param in [
"bufsize", "executable", "stdin", "stdout", "stderr",
"preexec_fn", "close_fds", "shell", "cwd", "env",
"universal_newlines", "startupinfo", "creationflags",
"restore_signals", "start_new_session", "pass_fds", "group",
"extra_groups", "user", "umask", "encoding", "errors", "text",
"pipesize", "process_group"]:
if local[param] is not FakePopen._unpassed:
proc_args[param] = local[param]
proc_info = self.get_info(proc_args)
result = FakeProcess(proc_args, proc_info)
self.procs.append(result)
return result
PopenFixture = FakePopen
|
