Many multiprocessing tests are silently skipped since 3.9

[serhiy-storchaka]

BPO	45042
Nosy	@pitrou, @vstinner, @ambv, @serhiy-storchaka, @applio, @miss-islington, @sobolevn
PRs	bpo-45042: Now test classes decorated with requires_hashdigest are not skipped #28060 [3.10] bpo-45042: Now test classes decorated with requires_hashdigest are not skipped (GH-28060) #28168 [3.9] bpo-45042: Now test classes decorated with `requires_hashdigest… #28169 bpo-45052: Unskips a failing test_shared_memory_basics test #28182

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-09-05.06:42:38.629>
created_at = <Date 2021-08-29.11:01:30.705>
labels = ['type-bug', 'tests', '3.9', '3.10', '3.11']
title = 'Many multiprocessing tests are silently skipped since 3.9'
updated_at = <Date 2021-09-20.07:49:54.187>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2021-09-20.07:49:54.187>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2021-09-05.06:42:38.629>
closer = 'serhiy.storchaka'
components = ['Tests']
creation = <Date 2021-08-29.11:01:30.705>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 45042
keywords = ['patch', '3.9regression']
message_count = 13.0
messages = ['400521', '400587', '400588', '400590', '400594', '400597', '400605', '400612', '400650', '401060', '401061', '401072', '402204']
nosy_count = 7.0
nosy_names = ['pitrou', 'vstinner', 'lukasz.langa', 'serhiy.storchaka', 'davin', 'miss-islington', 'sobolevn']
pr_nums = ['28060', '28168', '28169', '28182']
priority = 'high'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45042'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[serhiy-storchaka]

Here is a list of multiprocessing tests which are run in 3.8 but are not found in 3.9+:

OtherTest.test_answer_challenge_auth_failure
OtherTest.test_deliver_challenge_auth_failure
TestInitializers.test_manager_initializer
TestInitializers.test_pool_initializer
TestSyncManagerTypes.test_array
TestSyncManagerTypes.test_barrier
TestSyncManagerTypes.test_bounded_semaphore
TestSyncManagerTypes.test_condition
TestSyncManagerTypes.test_dict
TestSyncManagerTypes.test_event
TestSyncManagerTypes.test_joinable_queue
TestSyncManagerTypes.test_list
TestSyncManagerTypes.test_lock
TestSyncManagerTypes.test_namespace
TestSyncManagerTypes.test_pool
TestSyncManagerTypes.test_queue
TestSyncManagerTypes.test_rlock
TestSyncManagerTypes.test_semaphore
TestSyncManagerTypes.test_value
WithManagerTestBarrier.test_abort
WithManagerTestBarrier.test_abort_and_reset
WithManagerTestBarrier.test_action
WithManagerTestBarrier.test_barrier
WithManagerTestBarrier.test_barrier_10
WithManagerTestBarrier.test_default_timeout
WithManagerTestBarrier.test_reset
WithManagerTestBarrier.test_single_thread
WithManagerTestBarrier.test_thousand
WithManagerTestBarrier.test_timeout
WithManagerTestBarrier.test_wait_return
WithManagerTestCondition.test_notify
WithManagerTestCondition.test_notify_all
WithManagerTestCondition.test_notify_n
WithManagerTestCondition.test_timeout
WithManagerTestCondition.test_wait_result
WithManagerTestCondition.test_waitfor
WithManagerTestCondition.test_waitfor_timeout
WithManagerTestContainers.test_dict
WithManagerTestContainers.test_dict_iter
WithManagerTestContainers.test_dict_proxy_nested
WithManagerTestContainers.test_list
WithManagerTestContainers.test_list_iter
WithManagerTestContainers.test_list_proxy_in_list
WithManagerTestContainers.test_namespace
WithManagerTestEvent.test_event
WithManagerTestLock.test_lock
WithManagerTestLock.test_lock_context
WithManagerTestLock.test_rlock
WithManagerTestManagerRestart.test_rapid_restart
WithManagerTestMyManager.test_mymanager
WithManagerTestMyManager.test_mymanager_context
WithManagerTestMyManager.test_mymanager_context_prestarted
WithManagerTestPool.test_apply
WithManagerTestPool.test_async
WithManagerTestPool.test_async_timeout
WithManagerTestPool.test_context
WithManagerTestPool.test_empty_iterable
WithManagerTestPool.test_enter
WithManagerTestPool.test_imap
WithManagerTestPool.test_imap_handle_iterable_exception
WithManagerTestPool.test_imap_unordered
WithManagerTestPool.test_imap_unordered_handle_iterable_exception
WithManagerTestPool.test_make_pool
WithManagerTestPool.test_map
WithManagerTestPool.test_map_async
WithManagerTestPool.test_map_async_callbacks
WithManagerTestPool.test_map_chunksize
WithManagerTestPool.test_map_handle_iterable_exception
WithManagerTestPool.test_map_no_failfast
WithManagerTestPool.test_map_unplicklable
WithManagerTestPool.test_release_task_refs
WithManagerTestPool.test_resource_warning
WithManagerTestPool.test_starmap
WithManagerTestPool.test_starmap_async
WithManagerTestPool.test_terminate
WithManagerTestPool.test_traceback
WithManagerTestPool.test_wrapped_exception
WithManagerTestQueue.test_closed_queue_put_get_exceptions
WithManagerTestQueue.test_fork
WithManagerTestQueue.test_get
WithManagerTestQueue.test_no_import_lock_contention
WithManagerTestQueue.test_put
WithManagerTestQueue.test_qsize
WithManagerTestQueue.test_queue_feeder_donot_stop_onexc
WithManagerTestQueue.test_queue_feeder_on_queue_feeder_error
WithManagerTestQueue.test_task_done
WithManagerTestQueue.test_timeout
WithManagerTestRemoteManager.test_remote
WithManagerTestSemaphore.test_bounded_semaphore
WithManagerTestSemaphore.test_semaphore
WithManagerTestSemaphore.test_timeout
WithProcessesTestManagerRestart.test_rapid_restart
WithProcessesTestPicklingConnections.test_access
WithProcessesTestPicklingConnections.test_pickling
WithProcessesTestSharedMemory.test_shared_memory_ShareableList_basics
WithProcessesTestSharedMemory.test_shared_memory_ShareableList_pickling
WithProcessesTestSharedMemory.test_shared_memory_SharedMemoryManager_basics
WithProcessesTestSharedMemory.test_shared_memory_SharedMemoryManager_reuses_resource_tracker
WithProcessesTestSharedMemory.test_shared_memory_SharedMemoryServer_ignores_sigint
WithProcessesTestSharedMemory.test_shared_memory_across_processes
WithProcessesTestSharedMemory.test_shared_memory_basics
WithProcessesTestSharedMemory.test_shared_memory_cleaned_after_process_termination
WithThreadsTestManagerRestart.test_rapid_restart

[sobolevn]

Looks like that this happens because tests classes are decorated with @hashlib_helper.requires_hashdigest('md5'):

cpython/Lib/test/_test_multiprocessing.py

Lines 4482 to 4485 in 2a8127c

	@hashlib_helper.requires_hashdigest('md5')
	class OtherTest(unittest.TestCase):
	# TODO: add more tests for deliver/answer challenge.
	def test_deliver_challenge_auth_failure(self):

Tests above run fine without this decorator.
It was added in https://bugs.python.org/issue17258

The problem is that `` was treating a decorated entity as a function, not a class.

cpython/Lib/test/support/hashlib_helper.py

Line 25 in e6497fe

@functools.wraps(func)

But, it was decorating classes as well.
So, it needs to changed to respect classes.

I will make a PR shortly.

[pitrou]

Wow. I hope this didn't hide any regression :-(

[sobolevn]

Looks like it did, two newly-unignored tests are failing:
#28060 (comment)

пн, 30 авг. 2021 г. в 15:16, Antoine Pitrou <report@bugs.python.org>:

Antoine Pitrou <pitrou@free.fr> added the comment:

Wow. I hope this didn't hide any regression :-(

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Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue45042\>

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[serhiy-storchaka]

Thank you Nikita.

The difference between the original and the proposed in PR 28060 code is that in the original code the conditional was tested at the testing time, while in the proposed code it is tested at the loading time. I do not know what effect it causes on tests. If it does not matter, the code can be simpler:

   return unittest.skipIf(should_be_skipped,
                          f"hash digest '{digestname}' is not available.")

But if it matters, there are two options:

1. In requires_hashdigest() raise exception if func is a class. Remove the decorator from classes and add it to test and setup methods or just to the setUpClass() classmethod.

2. In requires_hashdigest() check if func is a class, and if it is true, patch its test and setup methods (or just add a decorated setUpClass() classmethod).