Description
I have strange console output problem if I have test that uses pytest and pywinauto. The problem can reproduced also by using uiautomation. I think the common underlying nominator is comtypes, but that is just guessing and I lack the skills to confirm that assumption.
The example test in below needs pywinauto and Notepad++ installed with new 1 tab active in the Notepad++ UI:
import subprocess
import time
import pywinauto
def test_pywinauto():
subprocess.Popen(r'C:/Program Files/Notepad++/notepad++.exe')
app = pywinauto.Application(backend='uia')
win = None
count = 0
while win is None:
try:
app.connect(title_re='new ')
win = app.window()
except pywinauto.ElementNotFoundError:
if count > 5:
raise
time.sleep(1)
finally:
count += 1
win.print_control_identifiers(filename='C:/tmp/print_control_identifiers_1212.log')When I run this test (In Windows 10, 1909 64bit) using Python 3.8.2:
python -m pytest test_pywinauto.py
then I see endless output in the cmd, see Github gits for part of the log. It looks like test does not end and logging is in some sort of endless loop. I did try pytest versions 5.4.1, 5.2.2, 5.0.1, 5.0.0 and 4.6.9 to see where the problem starts. All of the 5.x series had a similar problem but the 4.6.9 did not suffer from the same problem and test did execute without problems.
Then did do git bisect to try to trace the problem to a specific commit and after few good/bad commands, I did end up seeing this:
$ git bisect bad
a37b902afea21621639b114f087e84f70fb057ba is the first bad commit
commit a37b902afea21621639b114f087e84f70fb057ba
Author: Bruno Oliveira <[email protected]>
Date: Wed Jun 12 18:49:51 2019 -0300
Integrate pytest-faulthandler into the core
* Add pytest-faulthandler files unchanged
* Adapt imports and tests
* Add code to skip registration of the external `pytest_faulthandler`
to avoid conflicts
Fix #5440
changelog/5440.feature.rst | 8 ++++
doc/en/usage.rst | 19 +++++++-
src/_pytest/config/__init__.py | 3 +-
src/_pytest/deprecated.py | 8 ++++
src/_pytest/faulthandler.py | 102 +++++++++++++++++++++++++++++++++++++++++
testing/deprecated_test.py | 23 ++++------
testing/test_faulthandler.py | 99 +++++++++++++++++++++++++++++++++++++++
7 files changed, 245 insertions(+), 17 deletions(-)
create mode 100644 changelog/5440.feature.rst
create mode 100644 src/_pytest/faulthandler.py
create mode 100644 testing/test_faulthandler.pyNow if I run the above test with command (with pytest 5.4.1):
python -m pytest -p no:faulthandler test_pywinauto.py
console output problem is not present and test is executed successfully:
(venv) C:\tmp>python -m pytest -p no:faulthandler test_pywinauto.py
================================================= test session starts =================================================
platform win32 -- Python 3.8.2, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
rootdir: C:\tmp
collected 1 item
test_pywinauto.py . [100%]
================================================== warnings summary ===================================================
venv\lib\site-packages\win32\lib\pywintypes.py:2
C:\tmp\venv\lib\site-packages\win32\lib\pywintypes.py:2: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses
import imp, sys, os
-- Docs: https://docs.pytest.org/en/latest/warnings.html
============================================ 1 passed, 1 warning in 5.30s =============================================
(venv) C:\tmp>
Although there is a workaround available, it would be nice to understand why commit a37b902 causes such problem. This also could be in some way related to #5743 because when faulthandler is disabled, the console does not anymore contain lines saying: Windows fatal exception:....
My pip list looks like:
(venv) C:\tmp\pytest>pip list
Package Version
------------------ -------
appdirs 1.4.3
atomicwrites 1.3.0
attrs 19.3.0
cfgv 3.1.0
colorama 0.4.3
comtypes 1.1.7
distlib 0.3.0
filelock 3.0.12
identify 1.4.14
importlib-metadata 1.6.0
more-itertools 8.2.0
nodeenv 1.3.5
packaging 20.3
pip 20.0.2
pluggy 0.13.1
pre-commit 2.2.0
py 1.8.1
pyparsing 2.4.7
pytest 5.4.1
pywin32 227
pywinauto 0.6.8
PyYAML 5.3.1
setuptools 41.2.0
six 1.14.0
toml 0.10.0
tox 3.14.6
virtualenv 20.0.16
wcwidth 0.1.9
zipp 3.1.0
(venv) C:\tmp\pytes>