Regression 0.14.0 -> 0.14.1 in combination with pytest-xdist: execnet.gateway_base.DumpError: can't serialize ... #202
Description
We noticed a regression between pytest-subtests 0.14.0 and 0.14.1 when using it in combination with pytest-xdist.
When executing the following snippet with pytest -n 1 test.py:
import unittest
from enum import StrEnum, auto
class MyEnum(StrEnum):
A = auto()
B = auto()
class MyUnitTest(unittest.TestCase):
def test_enum_values(self):
for value in (MyEnum.A, MyEnum.B):
with self.subTest(value):
assert True
it passes with pytest-subtests 0.14.0, but fails with pytest-subtests 0.14.1 with the following error:
error
==================================================================================================================================================== FAILURES =====================================================================================================================================================
___________________________________________________________________________________________________________________________________________ MyUnitTest.test_enum_values ___________________________________________________________________________________________________________________________________________
[gw0] win32 -- Python 3.12.10 C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Scripts\python.exe
self = <test.MyUnitTest testMethod=test_enum_values>
def test_enum_values(self):
for value in (MyEnum.A, MyEnum.B):
> with self.subTest(value):
^^^^^^^^^^^^^^^^^^^
test.py:12:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
C:\Python312\Lib\contextlib.py:144: in __exit__
next(self.gen)
C:\Python312\Lib\contextlib.py:144: in __exit__
next(self.gen)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\pytest_subtests\plugin.py:140: in _addSubTest
self.ihook.pytest_runtest_logreport(report=sub_report)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\pluggy\_hooks.py:512: in __call__
return self._hookexec(self.name, self._hookimpls.copy(), kwargs, firstresult)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\pluggy\_manager.py:120: in _hookexec
return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\xdist\remote.py:289: in pytest_runtest_logreport
self.sendevent("testreport", data=data)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\xdist\remote.py:126: in sendevent
self.channel.send((name, kwargs))
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:912: in send
self.gateway._send(Message.CHANNEL_DATA, self.id, dumps_internal(item))
^^^^^^^^^^^^^^^^^^^^
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1629: in dumps_internal
return _Serializer().save(obj) # type: ignore[return-value]
^^^^^^^^^^^^^^^^^^^^^^^
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1647: in save
self._save(obj)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1667: in _save
dispatch(self, obj)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1744: in save_tuple
self._save(item)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1667: in _save
dispatch(self, obj)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1740: in save_dict
self._write_setitem(key, value)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1734: in _write_setitem
self._save(value)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1667: in _save
dispatch(self, obj)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1740: in save_dict
self._write_setitem(key, value)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1734: in _write_setitem
self._save(value)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1667: in _save
dispatch(self, obj)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1740: in save_dict
self._write_setitem(key, value)
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1734: in _write_setitem
self._save(value)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <execnet.gateway_base._Serializer object at 0x0000015DD841B440>, obj = <MyEnum.A: 'a'>
def _save(self, obj: object) -> None:
tp = type(obj)
try:
dispatch = self._dispatch[tp]
except KeyError:
methodname = "save_" + tp.__name__
meth: Callable[[_Serializer, object], None] | None = getattr(
self.__class__, methodname, None
)
if meth is None:
> raise DumpError(f"can't serialize {tp}") from None
E execnet.gateway_base.DumpError: can't serialize <enum 'MyEnum'>
C:\Users\randy\AppData\Local\pypoetry\Cache\virtualenvs\pytest-subtest-test-yf4kPUW1-py3.12\Lib\site-packages\execnet\gateway_base.py:1665: DumpError
---------------------------------------------------------------------------------------------------------------------------------------------- Captured stdout call -----------------------------------------------------------------------------------------------------------------------------------------------
,
============================================================================================================================================= short test summary info =============================================================================================================================================
FAILED test.py::MyUnitTest::test_enum_values - execnet.gateway_base.DumpError: can't serialize <enum 'MyEnum'>
================================================================================================================================================ 1 failed in 0.80s ================================================================================================================================================
Executing the tests without pytest-xdist (pytest test.py) still succeeds.
The error can also be reproduced with kwargs, e.g. with self.subTest(path=Path('.')).
Workaround: Cast all arguments of subTest() to str.