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Python3 + pytest + pytest-mock: Mocks leaking into other test functions breaking assertions?

NOTE: All Details about my setup (python version, modules etc) listed at bottom of question.

Apologies in advance if this issue is blatant, but i've been wrestling with it for several days now. Hopefully someone can shed some new light.

I'm in the process of converting unit tests for my personal project from unittest -> pytest. Previously I was using the built-in unittest.mock module, but now i'm trying to use the pytest-mock plugin instead.

I have a sneaking feeling that my tests are leaking mock objects into one another.

Here's why:

High-level details:

# Python version
Python 3.5.2

# Pytest version ( and plugins )
pytest==3.0.7
pytest-benchmark==3.1.0a2
pytest-catchlog==1.2.2
pytest-cov==2.4.0
pytest-ipdb==0.1.dev2
pytest-leaks==0.2.2
pytest-mock==1.6.0
pytest-rerunfailures==2.1.0
pytest-sugar==0.8.0
pytest-timeout==1.2.0
python-dateutil==2.6.0
python-dbusmock==0.16.7

When I run my tests using the following command:

py.test --pdb --showlocals -v -R : -k test_subprocess.py

Everything is fine till we get to test_subprocess_check_command_type. At which point I get the following error:

        # Set mock return types
        # mock_map_type_to_command.return_value = int

        # action
        with pytest.raises(TypeError) as excinfo:
            scarlett_os.subprocess.Subprocess(test_command,
                                              name=test_name,
                                              fork=test_fork,
>                                             run_check_command=True)
E           Failed: DID NOT RAISE <class 'TypeError'>

excinfo    = <[AttributeError("'ExceptionInfo' object has no attribute 'typename'") raised in repr()] ExceptionInfo object at 0x7f8c380f9dc0>
mock_fork  = <Mock name='mock_fork' id='140240122195184'>
mock_logging_debug = <Mock name='mock_logging_debug' id='140240128747640'>
mock_map_type_to_command = <Mock name='mock_map_type_to_command' id='140240122785112'>
mocker     = <pytest_mock.MockFixture object at 0x7f8c329f07a8>
monkeypatch = <_pytest.monkeypatch.MonkeyPatch object at 0x7f8c329f0810>
self       = <tests.test_subprocess.TestScarlettSubprocess object at 0x7f8c32aaac20>
test_command = ['who', '-b']
test_fork  = False
test_name  = 'test_who'

tests/test_subprocess.py:267: Failed

 tests/test_subprocess.py::TestScarlettSubprocess.test_subprocess_check_command_type ⨯                                                           100% ██████████

BUT!

If I filter out all of the other tests except for the problematic one then I get:

via py.test --pdb --showlocals -v -R : -k test_subprocess_check_command_type

pi@0728af726f1f:~/dev/bossjones-github/scarlett_os$ py.test --pdb --showlocals -v -R : -k test_subprocess_check_command_type
/usr/local/lib/python3.5/site-packages/_pdbpp_path_hack/pdb.py:4: ResourceWarning: unclosed file <_io.TextIOWrapper name='/usr/local/lib/python3.5/site-packages/pdb.py' mode='r' encoding='UTF-8'>
  os.path.dirname(os.path.dirname(__file__)), 'pdb.py')).read(), os.path.join(
Test session starts (platform: linux, Python 3.5.2, pytest 3.0.7, pytest-sugar 0.8.0)
cachedir: .cache
benchmark: 3.1.0a2 (defaults: timer=time.perf_counter disable_gc=False min_rounds=5 min_time=0.000005 max_time=1.0 calibration_precision=10 warmup=False warmup_iterations=100000)
rootdir: /home/pi/dev/bossjones-github/scarlett_os, inifile: setup.cfg
plugins: timeout-1.2.0, sugar-0.8.0, rerunfailures-2.1.0, mock-1.6.0, leaks-0.2.2, ipdb-0.1.dev2, cov-2.4.0, catchlog-1.2.2, benchmark-3.1.0a2
timeout: 60.0s method: signal
NOTE: DBUS_SESSION_BUS_ADDRESS environment var not found!
[DBUS_SESSION_BUS_ADDRESS]: unix:path=/tmp/dbus_proxy_outside_socket

 tests/test_subprocess.py::TestScarlettSubprocess.test_subprocess_check_command_type ✓                                                                                                                                                                           100% ██████████

Results (8.39s):
       1 passed
     190 deselected
pi@0728af726f1f:~/dev/bossjones-github/scarlett_os$

I also tried manually commenting out the following 2 tests and they allowed me to successfully run all the tests again:

  • test_subprocess_init
  • test_subprocess_map_type_to_command

Can anyone see anything blatently wrong with my setup? I've read several blog posts on "where to mock", and looked at the docs themselves several times, not sure what i'm missing. https://docs.python.org/3/library/unittest.mock.html

My Setup Details

Here is everything that might be required to solve this. Let me know if I need to provide any more information!

Also ... please excuse how messy my code looks and all of the comment blocks. I'm a big note taker when i'm learning something new ... I'll make everything more pythonic and cleaner in the near future :)

My code:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""Scarlett Dbus Service. Implemented via MPRIS D-Bus Interface Specification."""

from __future__ import with_statement, division, absolute_import

import os
import sys
from scarlett_os.exceptions import SubProcessError
from scarlett_os.exceptions import TimeOutError
import logging
from scarlett_os.internal.gi import GObject
from scarlett_os.internal.gi import GLib

logger = logging.getLogger(__name__)


def check_pid(pid):
    """Check For the existence of a unix pid."""
    try:
        os.kill(pid, 0)
    except OSError:
        return False
    else:
        return True


class Subprocess(GObject.GObject):
    """
    GObject API for handling child processes.

    :param command: The command to be run as a subprocess.
    :param fork: If `True` this process will be detached from its parent and
                 run independent. This means that no excited-signal will be emited.

    :type command: `list`
    :type fork: `bool`
    """

    __gtype_name__ = 'Subprocess'
    __gsignals__ = {
        'exited': (GObject.SignalFlags.RUN_LAST, None, (GObject.TYPE_INT, GObject.TYPE_INT))
    }

    def __init__(self, command, name=None, fork=False, run_check_command=True):
        """Create instance of Subprocess."""

        GObject.GObject.__init__(self)

        self.process = None
        self.pid = None

        if not fork:
            self.stdout = True
            self.stderr = True
        else:
            self.stdout = False
            self.stderr = False

        self.forked = fork

        # Verify that command is properly formatted 
        # and each argument is of type str
        if run_check_command:
            self.check_command_type(command)

        self.command = command
        self.name = name

        logger.debug("command: {}".format(self.command))
        logger.debug("name: {}".format(self.name))
        logger.debug("forked: {}".format(self.forked))
        logger.debug("process: {}".format(self.process))
        logger.debug("pid: {}".format(self.pid))

        if fork:
            self.fork()

    # TODO: Add these arguments so we can toggle stdout
    # def spawn_command(self, standard_input=False, standard_output=False, standard_error=False):
    def spawn_command(self):
        # DO_NOT_REAP_CHILD
        # Don't reap process automatically so it is possible to detect when it is closed.
        return GLib.spawn_async(self.command,
                                flags=GLib.SpawnFlags.SEARCH_PATH | GLib.SpawnFlags.DO_NOT_REAP_CHILD
                                )

    def map_type_to_command(self, command):
        """Return: Map after applying type to several objects in an array"""
        # NOTE: In python3, many processes that iterate over iterables return iterators themselves. 
        # In most cases, this ends up saving memory, and should make things go faster.
        # cause of that, we need to call list() over the map object
        return list(map(type, command))

    def check_command_type(self, command):

        types = self.map_type_to_command(command)

        if type(types) is not list:
            raise TypeError("Variable types should return a list in python3. Got: {}".format(types))

        # NOTE: str is a built-in function (actually a class) which converts its argument to a string. 
        # string is a module which provides common string operations.
        # source: http://stackoverflow.com/questions/2026038/relationship-between-string-module-and-str
        for t in types:
            if t is not str:
                raise TypeError("Executables and arguments must be str objects. types: {}".format(t))

        logger.debug("Running Command: %r" % " ".join(command))
        return True

    def run(self):
        """Run the process."""

        # NOTE: DO_NOT_REAP_CHILD: the child will not be automatically reaped;
        # you must use g_child_watch_add yourself (or call waitpid or handle `SIGCHLD` yourself),
        # or the child will become a zombie.
        # source:
        # http://valadoc.org/#!api=glib-2.0/GLib.SpawnFlags.DO_NOT_REAP_CHILD

        # NOTE: SEARCH_PATH: argv[0] need not be an absolute path, it will be looked for in the user's PATH
        # source:
        # http://lazka.github.io/pgi-docs/#GLib-2.0/flags.html#GLib.SpawnFlags.SEARCH_PATH

        self.pid, self.stdin, self.stdout, self.stderr = self.spawn_command()

        logger.debug("command: {}".format(self.command))
        logger.debug("stdin: {}".format(self.stdin))
        logger.debug("stdout: {}".format(self.stdout))
        logger.debug("stderr: {}".format(self.stderr))
        logger.debug("pid: {}".format(self.pid))

        # close file descriptor
        self.pid.close()

        print(self.stderr)

        # NOTE: GLib.PRIORITY_HIGH = -100
        # Use this for high priority event sources.
        # It is not used within GLib or GTK+.
        watch = GLib.child_watch_add(GLib.PRIORITY_HIGH, 
                                     self.pid, 
                                     self.exited_cb)

        return self.pid

    def exited_cb(self, pid, condition):
        if not self.forked:
            self.emit('exited', pid, condition)

    def fork(self):
        """Fork the process."""
        try:
            # first fork
            pid = os.fork()
            if pid > 0:
                logger.debug('pid greater than 0 first time')
                sys.exit(0)
        except OSError as e:
            logger.error('Error forking process first time')
            sys.exit(1)

        # Change the current working directory to path.
        os.chdir("/")

        # Description: setsid() creates a new session if the calling process is not a process group leader. 
        # The calling process is the leader of the new session, 
        # the process group leader of the new process group, 
        # and has no controlling terminal. 
        # The process group ID and session ID of the calling process are set to the PID of the calling process. 
        # The calling process will be the only process in this new process group and in this new session.

        # Return Value: On success, the (new) session ID of the calling process is returned. 
        # On error, (pid_t) -1 is returned, and errno is set to indicate the error.
        os.setsid()

        # Set the current numeric umask and return the previous umask.
        os.umask(0)

        try:
            # second fork
            pid = os.fork()
            if pid > 0:
                logger.debug('pid greater than 0 second time')
                sys.exit(0)
        except OSError as e:
            logger.error('Error forking process second time')
            sys.exit(1)

My Test:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
test_subprocess
----------------------------------
"""

import os
import sys
import pytest

import scarlett_os
# import signal
# import builtins
# import re

class TestScarlettSubprocess(object):
    '''Units tests for Scarlett Subprocess, subclass of GObject.Gobject.'''

    def test_check_pid_os_error(self, mocker):
        # Feels like mocks are leaking into other tests, 
        # stop mock before starting each test function
        mocker.stopall()

        # Setup mock objects
        kill_mock = mocker.MagicMock(name=__name__ + "_kill_mock_OSError")
        kill_mock.side_effect = OSError

        # patch things
        mocker.patch.object(scarlett_os.subprocess.os, 'kill', kill_mock)

        # When OSError occurs, throw False
        assert not scarlett_os.subprocess.check_pid(4353634632623)
        # Verify that os.kill only called once
        assert kill_mock.call_count == 1

    def test_check_pid(self, mocker):
        # Feels like mocks are leaking into other tests, 
        # stop mock before starting each test function
        mocker.stopall()

        # Setup mock objects
        kill_mock = mocker.MagicMock(name=__name__ + "_kill_mock")

        mocker.patch.object(scarlett_os.subprocess.os, 'kill', kill_mock)

        result = scarlett_os.subprocess.check_pid(123)
        assert kill_mock.called
        # NOTE: test against signal 0
        # sending the signal 0 to a given PID just checks if any
        # process with the given PID is running and you have the
        # permission to send a signal to it.
        kill_mock.assert_called_once_with(123, 0)
        assert result is True

    # FIXME: I THINK THIS GUYS IS LEAKING MOCK OBJECTS
    def test_subprocess_init(self, mocker):
        # Feels like mocks are leaking into other tests, 
        # stop mock before starting each test function
        mocker.stopall()

        mock_check_command_type = MagicMock(name="mock_check_command_type")
        mock_check_command_type.return_value = True
        mock_fork = mocker.MagicMock(name="mock_fork")
        mock_logging_debug = mocker.MagicMock(name="mock_logging_debug")

        # mock
        mocker.patch.object(scarlett_os.subprocess.logging.Logger, 'debug', mock_logging_debug)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'check_command_type', mock_check_command_type)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'fork', mock_fork)

        # NOTE: On purpose this is an invalid cmd. Should be of type array
        test_command = ['who']

        test_name = 'test_who'
        test_fork = False

        s_test = scarlett_os.subprocess.Subprocess(test_command,
                                                   name=test_name,
                                                   fork=test_fork)

        # action
        assert s_test.check_command_type(test_command) is True
        mock_check_command_type.assert_called_with(['who'])
        assert not s_test.process
        assert not s_test.pid
        assert s_test.name == 'test_who'
        assert not s_test.forked
        assert s_test.stdout is True
        assert s_test.stderr is True

        mock_logging_debug.assert_any_call("command: ['who']")
        mock_logging_debug.assert_any_call("name: test_who")
        mock_logging_debug.assert_any_call("forked: False")
        mock_logging_debug.assert_any_call("process: None")
        mock_logging_debug.assert_any_call("pid: None")
        mock_fork.assert_not_called()

    # FIXME: I THINK THIS GUYS IS LEAKING MOCK OBJECTS
    def test_subprocess_map_type_to_command(self, mocker):
        """Using the mock.patch decorator (removes the need to import builtins)"""
        # Feels like mocks are leaking into other tests, 
        # stop mock before starting each test function
        mocker.stopall()

        mock_check_command_type = mocker.MagicMock(name="mock_check_command_type")
        mock_check_command_type.return_value = True
        mock_fork = mocker.MagicMock(name="mock_fork")
        mock_logging_debug = mocker.MagicMock(name="mock_logging_debug")

        # mock
        mocker.patch.object(scarlett_os.subprocess.logging.Logger, 'debug', mock_logging_debug)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'check_command_type', mock_check_command_type)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'fork', mock_fork)

        # NOTE: On purpose this is an invalid cmd. Should be of type array
        test_command = ["who", "-b"]
        test_name = 'test_who'
        test_fork = False

        # create subprocess object
        s_test = scarlett_os.subprocess.Subprocess(test_command,
                                                   name=test_name,
                                                   fork=test_fork)
        mocker.spy(s_test, 'map_type_to_command')
        assert isinstance(s_test.map_type_to_command(test_command), list)
        assert s_test.map_type_to_command.call_count == 1

        assert s_test.check_command_type(test_command)
        assert s_test.check_command_type(
            test_command) == mock_check_command_type.return_value

    def test_subprocess_check_command_type(self, mocker):
        """Using the mock.patch decorator (removes the need to import builtins)"""
        # Feels like mocks are leaking into other tests, 
        # stop mock before starting each test function
        mocker.stopall()

        test_command = ["who", "-b"]
        test_name = 'test_who'
        test_fork = False

        # mock
        mock_map_type_to_command = mocker.MagicMock(name="mock_map_type_to_command")
        # mock_map_type_to_command.return_value = int
        mock_map_type_to_command.side_effect = [int, [int, int]]
        mock_fork = mocker.MagicMock(name="mock_fork")
        mock_logging_debug = mocker.MagicMock(name="mock_logging_debug")

        mocker.patch.object(scarlett_os.subprocess.logging.Logger, 'debug', mock_logging_debug)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'map_type_to_command', mock_map_type_to_command)
        mocker.patch.object(scarlett_os.subprocess.Subprocess, 'fork', mock_fork)


        # action
        with pytest.raises(TypeError) as excinfo:
            scarlett_os.subprocess.Subprocess(test_command,
                                              name=test_name,
                                              fork=test_fork,
                                              run_check_command=True)
        assert str(
            excinfo.value) == "Variable types should return a list in python3. Got: <class 'int'>"

        with pytest.raises(TypeError) as excinfo:
            scarlett_os.subprocess.Subprocess(test_command,
                                              name=test_name,
                                              fork=test_fork,
                                              run_check_command=True)

        assert str(
            excinfo.value) == "Executables and arguments must be str objects. types: <class 'int'>"

My folder structure( Note I removed a couple things since it was overly verbose ):

pi@0728af726f1f:~/dev/bossjones-github/scarlett_os$ tree -I *.pyc
.
├── requirements_dev.txt
├── requirements_test_experimental.txt
├── requirements_test.txt
├── requirements.txt
├── scarlett_os
│   ├── automations
│   │   ├── __init__.py
│   │   └── __pycache__
│   ├── commands.py
│   ├── compat.py
│   ├── config.py
│   ├── const.py
│   ├── core.py
│   ├── emitter.py
│   ├── exceptions.py
│   ├── __init__.py
│   ├── internal
│   │   ├── debugger.py
│   │   ├── deps.py
│   │   ├── encoding.py
│   │   ├── formatting.py
│   │   ├── gi.py
│   │   ├── __init__.py
│   │   ├── path.py
│   │   ├── __pycache__
│   │   └── system_utils.py
│   ├── listener.py
│   ├── loader.py
│   ├── logger.py
│   ├── log.py
│   ├── __main__.py
│   ├── mpris.py
│   ├── player.py
│   ├── __pycache__
│   ├── receiver.py
│   ├── speaker.py
│   ├── subprocess.py
│   ├── tasker.py
│   ├── tools
│   │   ├── __init__.py
│   │   ├── package.py
│   │   ├── __pycache__
│   │   └── verify.py
│   └── utility
│       ├── audio.py
│       ├── dbus_runner.py
│       ├── dbus_utils.py
│       ├── distance.py
│       ├── dt.py
│       ├── file.py
│       ├── generators.py
│       ├── gnome.py
│       ├── __init__.py
│       ├── location.py
│       ├── __pycache__
│       ├── temperature.py
│       ├── threadmanager.py
│       ├── thread.py
│       ├── unit_system.py
│       └── yaml.py
├── setup.cfg
├── setup.py
├── tests
│   ├── common_integration.py
│   ├── common.py
│   ├── helpers
│   │   ├── __init__.py
│   │   ├── __pycache__
│   │   ├── test_config_validation.py
│   │   ├── test_entity.py
│   │   └── test_init.py
│   ├── __init__.py
│   ├── integration
│   │   ├── baseclass.py
│   │   ├── conftest.py
│   │   ├── __init__.py
│   │   ├── __pycache__
│   │   ├── README.md
│   │   ├── stubs.py
│   │   ├── test_integration_end_to_end.py
│   │   ├── test_integration_listener.py
│   │   ├── test_integration_mpris.py
│   │   ├── test_integration_player.py
│   │   ├── test_integration_tasker.py
│   │   ├── test_integration_tasker.py.enable_sound.diff
│   │   └── test_integration_threadmanager.py
│   ├── internal
│   │   ├── __init__.py
│   │   ├── __pycache__
│   │   ├── test_deps.py
│   │   ├── test_encoding.py
│   │   └── test_path.py
│   ├── performancetests
│   │   ├── baseclass.py
│   │   ├── __init__.py
│   │   └── __pycache__
│   ├── __pycache__
│   ├── run_all_tests
│   ├── run_dbus_tests.sh
│   ├── test_cli.py
│   ├── test_commands.py
│   ├── testing_config
│   │   └── custom_automations
│   │       ├── light
│   │       │   └── test.py
│   │       └── switch
│   │           └── test.py
│   ├── test_listener.py
│   ├── test_mpris.py
│   ├── test_player.py
│   ├── test_scarlett_os.py
│   ├── test_speaker.py
│   ├── test_subprocess.py
│   ├── test_tasker.py
│   ├── test_threadmanager.py
│   ├── tools_common.py
│   ├── unit_scarlett_os.py
│   └── utility
│       ├── __init__.py
│       ├── __pycache__
│       ├── test_dbus_utils.py
│       ├── test_distance.py
│       ├── test_dt.py
│       ├── test_gnome.py
│       ├── test_init.py
│       ├── test_location.py
│       ├── test_unit_system.py
│       └── test_yaml.py
67 directories, 256 files
pi@0728af726f1f:~/dev/bossjones-github/scarlett_os$

Other details( Extended pip freeze just in case of incompatibilities ):

# Python version
Python 3.5.2

# Pytest version ( and plugins )
pytest==3.0.7
pytest-benchmark==3.1.0a2
pytest-catchlog==1.2.2
pytest-cov==2.4.0
pytest-ipdb==0.1.dev2
pytest-leaks==0.2.2
pytest-mock==1.6.0
pytest-rerunfailures==2.1.0
pytest-sugar==0.8.0
pytest-timeout==1.2.0
python-dateutil==2.6.0
python-dbusmock==0.16.7


# Pip Freeze ( Just in case )
alabaster==0.7.10
appdirs==1.4.3
argh==0.26.2
asn1crypto==0.22.0
astroid==1.5.2
Babel==2.4.0
bleach==2.0.0
bumpversion==0.5.3
cffi==1.10.0
click==6.7
click-plugins==1.0.3
colorama==0.3.7
colorlog==2.10.0
coverage==4.3.4
coveralls==1.1
cryptography==1.8.1
Cython==0.25.2
decorator==4.0.11
docopt==0.6.2
docutils==0.13.1
ecdsa==0.13
entrypoints==0.2.2
Fabric3==1.12.post1
fancycompleter==0.7
fields==5.0.0
flake8==3.3.0
flake8-docstrings==1.0.3
flake8-polyfill==1.0.1
freezegun==0.3.8
gnureadline==6.3.3
graphviz==0.6
html5lib==0.999999999
hunter==1.4.1
idna==2.5
imagesize==0.7.1
ipdb==0.10.2
ipykernel==4.6.1
ipython==6.0.0
ipython-genutils==0.2.0
ipywidgets==6.0.0
isort==4.2.5
jedi==0.10.2
Jinja2==2.9.6
jsonschema==2.6.0
jupyter==1.0.0
jupyter-client==5.0.1
jupyter-console==5.1.0
jupyter-core==4.3.0
lazy-object-proxy==1.2.2
MarkupSafe==1.0
mccabe==0.6.1
mistune==0.7.4
mock==2.0.0
mock-open==1.3.1
mypy-lang==0.4.6
nbconvert==5.1.1
nbformat==4.3.0
notebook==5.0.0
objgraph==3.1.0
ordereddict==1.1
packaging==16.8
pandocfilters==1.4.1
paramiko==1.18.2
pathtools==0.1.2
pbr==1.10.0
pdbpp==0.8.3
pexpect==4.2.1
pickleshare==0.7.4
pluggy==0.4.0
plumbum==1.6.3
prompt-toolkit==1.0.14
psutil==5.2.2
ptyprocess==0.5.1
py==1.4.33
py-cpuinfo==3.2.0
pyasn1==0.2.3
pycodestyle==2.3.1
pycparser==2.17
pycrypto==2.6.1
pydbus==0.6.0
pydocstyle==2.0.0
pyflakes==1.5.0
pygal==2.3.1
pygaljs==1.0.1
Pygments==2.2.0
pygobject==3.22.0
pylint==1.7.1
pyparsing==2.2.0
pystuck==0.8.5
pytest==3.0.7
pytest-benchmark==3.1.0a2
pytest-catchlog==1.2.2
pytest-cov==2.4.0
pytest-ipdb==0.1.dev2
pytest-leaks==0.2.2
pytest-mock==1.6.0
pytest-rerunfailures==2.1.0
pytest-sugar==0.8.0
pytest-timeout==1.2.0
python-dateutil==2.6.0
python-dbusmock==0.16.7
pytz==2017.2
PyYAML==3.12
pyzmq==16.0.2
qtconsole==4.3.0
requests==2.13.0
requests-mock==1.3.0
rpyc==3.3.0
-e [email protected]:bossjones/scarlett_os.git@c14ffcde608da12f5c2d4d9b81a63c7e618b3eed#egg=scarlett_os
simplegeneric==0.8.1
six==1.10.0
snowballstemmer==1.2.1
Sphinx==1.5.5
stevedore==1.18.0
termcolor==1.1.0
terminado==0.6
testpath==0.3
tornado==4.5.1
tox==2.7.0
traitlets==4.3.2
typing==3.6.1
virtualenv==15.0.3
virtualenv-clone==0.2.6
virtualenvwrapper==4.7.2
voluptuous==0.9.3
watchdog==0.8.3
wcwidth==0.1.7
webencodings==0.5.1
widgetsnbextension==2.0.0
wmctrl==0.3
wrapt==1.10.10
xdot==0.7

Edit: ( One more detail, why didn't I just us the patch context manager or decorators ? )

pytest-mock has a pretty good section on their design choice, and why they decided to move away from nested with statements and decorators piled on top of each other. Link is here, but let me mention a couple here just in case:

- excessive nesting of with statements breaking the flow of test
- receiving the mocks as parameters doesn't mix nicely with pytest's approach of naming fixtures as parameters, or pytest.mark.parametrize;

So, if it is possible to make my code a bit cleaner using this plugin, I would like to make that happen. If that isn't possible, then maybe I need to reconsider things.

like image 493
Malcolm Jones Avatar asked Apr 29 '17 17:04

Malcolm Jones


1 Answers

Why not run your mocks with function decorators or context managers to make sure they get closed out? For example, in test_subprocess_map_type_to_command, instead of doing all of this to mock scarlett_os.subprocess.Subprocess.check_command_type:

mock_check_command_type = mocker.MagicMock(name="mock_check_command_type")
mock_check_command_type.return_value = True
mocker.patch.object(scarlett_os.subprocess.Subprocess, 'check_command_type', mock_check_command_type)

Why not instead just use a context manager and do:

with mock.patch.object(
    scarlett_os.subprocess.Subprocess,
    'check_command_type',
    return_value=True):

It'll be much terser, and will make sure your mock doesn't leak.

Even better, if your mocks apply to the whole function (I think some of them do), you can use a decorator at the top of the function:

@mock.patch('scarlett_os.subprocess.Subprocess.check_command_type', 
            return_value=True)
like image 186
Eli Avatar answered Oct 08 '22 11:10

Eli