pytest with workers ( -n 1 for example ) using xdist when test contains also multiprocessing

Question

I'm using

Python 3.6
Pytest 6.1.1
Pytest xdist 2.1.0
Pycharm 2018.3.7

Using HTML plugin for report as well with customization for the report

I'm running automation test via pycharm >pytest with arguments as below: --html=../../reports/report.html --self-contained-html -n 1 -k test_instalment_mtn_ng_unified_eco

in order to capture the screen during selenium, i'm using multprocessing, that start the capturing, and continue with the test

if i'm NOT using in arguments -n 1 ( means no workers) -test passed successfully ( include screen capture)

if i'm using -n 1 ( means 1 worker) pytest crush with the follow error:

mtn_ng_tests/mtn_ng_instalment_tests/test_instalment_mtn_ng_unified_eco.py::test_instalment_mtn_ng_unified_eco[customer buy 3 months happy flow while in light-instalment_mtn_ng_unified_eco_1-3-eco-48-40-0-10-ACTIVATED-ACTIVATED-owner_phone_unified_happy_flow_mtn_ng_eco-unified_mtn_instalment_subscribe_charge_event-activation_flow_mtn_unified_instalmant_and_unsub-no-unified_mtn_instalment_unsubscribe_charge_event-sms0-false-None-false-mtn_l20_unified--free_sms0-ACTIVATION-true-Assigned to customer-Ready For Install-false--components_end_time_delta0] 
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/_pytest/main.py", line 257, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/_pytest/main.py", line 313, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/hooks.py", line 286, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/manager.py", line 93, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/manager.py", line 87, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/xdist/dsession.py", line 112, in pytest_runtestloop
INTERNALERROR>     self.loop_once()
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/xdist/dsession.py", line 135, in loop_once
INTERNALERROR>     call(**kwargs)
INTERNALERROR>   File "/home/ohad/.local/lib/python2.7/e2e/lib/python3.6/site-packages/xdist/dsession.py", line 174, in worker_workerfinished
INTERNALERROR>     **assert not crashitem, (crashitem, node)**
INTERNALERROR> AssertionError: ('E2eAutomation/tests/mtn_ng_tests/mtn_ng_instalment_tests/test_instalment_mtn_ng_unified_eco.py::test_instalment_mtn_...ms0-ACTIVATION-true-Assigned to customer-Ready For Install-false--components_end_time_delta0]', <WorkerController gw0>)
INTERNALERROR> assert not 'E2eAutomation/tests/mtn_ng_tests/mtn_ng_instalment_tests/test_instalment_mtn_ng_unified_eco.py::test_instalment_mtn_n...e-mtn_l20_unified--free_sms0-ACTIVATION-true-Assigned to customer-Ready For Install-false--components_end_time_delta0]'

googled it for 2 days, and didnt found what could be the reason Attaching part of the test code Thanks in advance

# @pytest.mark.skip(reason='relax for now :)')
@pytest.mark.sanity
@pytest.mark.regression
@pytest.mark.instalment_mtn_ng
@pytest.mark.parametrize("scenario_description,unit,month,unit_type,customer_deal,time_unit_purchased,"
                         "set_desired,light_dark,unit_set_state,unit_expected_state,"
                         "owner_phone,charge_event_flow,activation_flow_job_scenario,"
                         "real_unit,charge_event_flow_unsub,sms,ipp_flow,set_product_id,free_triggered,instalment_type,"
                         "free_job_flow,free_sms,unit_status_during_process,valid_product,"
                         "set_crm_unit_status,get_crm_unit_status,set_last_day_of_month,notes,components_end_time_delta",
                         load_data_driven_for_test(profile='instalment_mtn_ng_eco'))
@pytest.mark.skipif(os.environ.get('DRY_RUN') == "True", reason="Jenkins Dry Run")
def test_instalment_mtn_ng_unified_eco(scenario_description, unit, month, unit_type, customer_deal, time_unit_purchased,
                                       set_desired, light_dark,
                                       unit_set_state, unit_expected_state, owner_phone, charge_event_flow,
                                       activation_flow_job_scenario, real_unit, charge_event_flow_unsub, sms, ipp_flow,
                                       set_product_id, free_triggered, instalment_type, free_job_flow, free_sms,
                                       unit_status_during_process, valid_product, set_crm_unit_status,
                                       get_crm_unit_status,
                                       set_last_day_of_month, notes, components_end_time_delta,
                                       setup, record_property):
    # ==================================================================================== Test yield from fixture

    lms_cursor, db_conn, lms_user, locale_sms, lms_db_connection, crm_db_connection, crm_cursor, soap_port = \
        setup[0], setup[1], setup[2], setup[3], setup[4], setup[5], setup[6], setup[7]

    # ====================================== Log creation ================================================
    os.environ['TEST_NUMBER'] = str(int(os.environ.get('TEST_NUMBER')) + 1)
    now = datetime.datetime.now()
    time_stamp = f"{now.year}{now.month}{now.day}{now.hour}{now.minute}{now.second}"
    os.environ['TEST_NAME'] = f"{os.path.basename(__file__)[:-3]}_#_{os.environ.get('TEST_NUMBER')}_" \
                                  f"{scenario_description.replace(' ', '_')}_" + time_stamp
    logging = setting_log.log_config.setup_logger()

    # ==================================================================================== Video recording
    if   os.environ.get('PYTEST_XDIST_WORKER_COUNT'):  # no workers so run with video capture
        video_record = multiprocessing.Process(target=ScreenVideo().execute_video_capturing)
        video_record.start()

        # ==================================================================================== Test Tear Down
        logging.info("test tear down")
        record_property("test_returns", {"screen_recorder": video_record})
        # record_property("test_returns", {"screen_recorder": video_record, "selenium_driver": automation_utils})
    else:
        logging.info("test tear down")
        record_property("test_returns", {})

    # ========================================================Initiate logs that not created in main fixture
    assert 1==2 (just to falied the test quicker)

`-n1` doesn't mean "no workers". Rerun the test with `-n0` and check whether the assertion error is raised. — hoefling, Oct 27 '20 at 20:19
i meant when i'm removing the -n 1 from the argument >>> it means i'm not using workers, and all run ok. example :html=../../reports/report.html --self-contained-html -k test_instalment_mtn_ng_unified_eco. the problem occured when i'm using -n 1 -the goal is to use several workers of course in order to run in parallel tests — ohadshay, Oct 27 '20 at 21:44
When I do not use -n 3 in the arguments, it means I’m using no workers, and all tests will run one by one serially. So far so good. I also managed to run with workers (-n 3 for instance) and all tests run in parallel as expected. My problem started, when I add to test body (def test_1: for instance) multi processing ( for screen frame capture to run in background while test is running) Now, If I use no worksers but tests use multi processing, all run as expected. When I use workers, I get this exceptions ( it occurs only due to the multiprocessing in the test it self that I’m using — ohadshay, Oct 27 '20 at 21:54

score 1 · Answer 1 · answered Nov 18 '20 at 19:54

I faced the same error a few days ago and I found that the bug is in the record_property fixture

For some reason, the record_property fixture does not accept receiving some types of data. In my case, I was trying to pass the response from an API request to the record_property fixture, something like:

record_property("api_res", res)

After several attempts, I created a workaround to send the response from API request via record_property fixture and store the informations that I needed:

@pytest.fixture
def store_api_response(record_property, request):
        record_property(
            'api_res', {
                'request_url': str(response.request.method + env + response.request.path_url),
                'headers': dict(response.request.headers),
                'request_body': response.request.body,
                'response_body': response_body,
                'status_code': str(response.status_code)
            }
        )
    return get_response

In your case, the error happens exactly on this line:

record_property("test_returns", {"screen_recorder": video_record})

The record_property fixture is not accepting the data stored in the video_record variable

pytest with workers ( -n 1 for example ) using xdist when test contains also multiprocessing

1 Answers1