pytest log_cli + standard logging = breaks doctest

Question

We're using pytest and python std logging, and have some tests in doctests. We'd like to enable log_cli to make debugging tests in ide easier (lets stderr flow to the "live" console so one can see log statements as they are output when stepping through) The problem is there appears to be a bug/iteraction between "use of logging" (eg presence of a call to logger.info("...") etc) log_cli=true.

I don't see any other flags or mention of this in the docs, so it appears to be a bug, but was hoping there is a workaround.

This test module passes:

# bugjar.py
"""
>>> dummy()
'retval'
"""
import logging
logger = logging.getLogger(__name__)
def dummy():
    # logger.info("AnInfoLog")  ## un-comment to break test
    return "retval"

but un-commenting (no other changes) the logger.info( call causes a failure: (unless i remove log_cli from pytest.ini)

002 >>> dummy()
Expected:
    'retval'
Got nothing

Here is my command line & relevant version output(s):

(venv) $ ./venv/bin/pytest -c ./pytest.ini ./bugjar.py
======================================================================= test session starts ========================================================================
platform linux -- Python 3.8.5, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: -omitted-/test-unit, configfile: ./pytest.ini
plugins: forked-1.3.0, xdist-2.2.1, profiling-1.7.0
collected 1 item                                                                                                                                                   

bugjar.py::bugjar
 
bugjar.py::bugjar 
-------------------------------------------------------------------------- live log call ---------------------------------------------------------------------------
INFO     bugjar:bugjar.py:8 AnInfoLog
FAILED                                                                                                                                                       [100%]

============================================================================= FAILURES =============================================================================
_________________________________________________________________________ [doctest] bugjar _________________________________________________________________________
001 
002 >>> dummy()
Expected:
    'retval'
Got nothing

and my pytest.ini (Note, commments are correct, pass/fail is not affected by use of logfile or other addopts

[pytest]
addopts = --doctest-modules # --profile --profile-svg 
norecursedirs = logs bin tmp* scratch venv* data
# log_file = pytest.log
log_cli = true
log_cli_level=debug

removing log_cli* from pytest.ini makes the issue go away.

This seems clearly related to what log_cli is manipulating, in capturing output for use in the doctest itself, but also not the expected behavior.

I am hoping I've made a mistake, or there is a workaround to get live log output in bash or IDE shell window / debugger.

pytest log_cli + standard logging = breaks doctest

0 Answers