pytest-profiling: File name can become too long on Windows

[danielschenk]

I have a parametrized test of which one of the invocations uses a (fairly long) byte string as input. Because pytest tries to print parametrized tests in the most useful way, this byte string ends up in the full test name, which pytest-profiling then uses for the file with the profiling results. This causes an issue on Windows which (unfortunately) has a fairly short file name length limit:

pytest --profile
============================= test session starts =============================
platform win32 -- Python 3.7.3, pytest-5.1.0, py-1.8.0, pluggy-0.12.0
rootdir: C:\Software\tryout\pytest_tryouts
plugins: cov-2.7.1, ordering-0.6, profiling-1.7.0, pycharm-0.6.0
collected 1 item

test_foo.py .                                                            [100%]
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\_pytest\main.py", line 191, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\_pytest\main.py", line 235, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\hooks.py", line 289, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\_pytest\main.py", line 256, in pytest_runtestloop
INTERNALERROR>     item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\hooks.py", line 289, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\manager.py", line 87, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\manager.py", line 81, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pluggy\callers.py", line 203, in _multicall
INTERNALERROR>     gen.send(outcome)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\site-packages\pytest_profiling.py", line 80, in pytest_runtest_protocol
INTERNALERROR>     prof.dump_stats(prof_filename)
INTERNALERROR>   File "c:\users\rnd10\appdata\local\programs\python\python37-32\lib\cProfile.py", line 46, in dump_stats
INTERNALERROR>     with open(file, 'wb') as f:
INTERNALERROR> OSError: [Errno 22] Invalid argument: 'C:\\Software\\tryout\\pytest_tryouts\\prof\\test_foo[_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff_xff].prof'

============================== 1 passed in 0.02s ==============================

Is this something pytest-profiling could handle in some way? It would be a pity if I could not write tests like this one and profile them 🤔

[eeaston]

Thanks for raising - yes the plugin should truncate the name on Windows. Sorry for the ridiculously long time to reply!