[py-dev] Decorators and funcargs in py.test

[holger krekel]

Hi Vyacheslav, hi Ronny,

On Mon, May 30, 2011 at 22:38 +0200, Ronny Pfannschmidt wrote:
> On Mon, 2011-05-30 at 16:23 -0400, Vyacheslav Rafalskiy wrote:
> > No problem. Here is my (real life) example.
> > 
> > My functional test functions may or may not return for different
> > reasons (like a faulty web application or middleware). I want to
> > declare a fail if it takes more than so many seconds to complete. So I
> > write a decorator
> > run_with_timeout(), which will start the function in a new thread and
> > abandon it after timeout.
> 
> This can easily be solved by combining something like
> pytest.mark('timeout') and a override to pytest_pyfunc_call using it

I agree.

Vyacheslav, if you can't make sense of the "use pytest.mark()" and
provide-a-hook suggestion, one of us will be certainly be happy to
provide a more complete example and add it to the docs.

> i suppose this could also take a look at extending the "--boxed" mode
> (which forks for each test and uses subprocesses but doesn’t handle
> timeouts atm.

this is part of the pytest-xdist plugin, however.  Question is,
if we shouldn't eventually grow timeout-support in core pytest
through "alarm" or so.

best,
holger

> > 
> > A I stated in OP, it is not that I cannot do it. I can and I do. My
> > point is that it makes sense to allow decorators and should not be
> > very difficult (see the example in OP).
> 
> personally i am opposed to creating new data conventions for problems
> that can be solved with plain marks + a hook
> 
> usually there are 2 reasons people use to decorate tests
> 
> my opinions for implementing those are 
> a) add arguments + their cleanups -> funcargs please, they are made for
> that
> b) use more sophisticated call's -> hooks please, maybe add a bug ticket
> for empowering one to return a exception-info, so stuff like
> thread-wrappers can pass that more nicely for failures
> 
> *i* really think it is wrong to decorate test functions that way and
> expect stuff to work
> 
> there are already plenty of mechanisms to change the behavior of pytest
> test function calling in the desired way, none of those require hacks to
> pass around argspecs
> 
> -- Ronny
> > 
> > Thanks,
> > Vyacheslav
> > 
> > On Mon, May 30, 2011 at 3:55 PM, Ronny Pfannschmidt
> > <Ronny.Pfannschmidt at gmx.de> wrote:
> > > Hi,
> > >
> > > can you try to explain the usecase those decorators are fulfilling,
> > >
> > > there may be a better integrated way using pytest.mark + setup/teardown
> > > hooks
> > >
> > > -- Ronny
> > >
> > > On Mon, 2011-05-30 at 15:17 -0400, Vyacheslav Rafalskiy wrote:
> > >> Hi Holger,
> > >>
> > >> I am trying to make decorators work with test functions, which depend
> > >> on funcargs. As it stands, they don't.
> > >> Decorated functions lose funcargs. A workaround would be to decorate
> > >> an internal function like this:
> > >>
> > >> def test_it(funcarg_it):
> > >>     @decorate_it
> > >>     def _test_it():
> > >>         # test it
> > >>
> > >>     _test_it()
> > >>
> > >> This works, but it is not nice. I'd rather wrote a decorator like
> > >>
> > >> def decorate_it(f):
> > >>     def _wrap_it(*args, **kwargs):
> > >>         # wrap f() here
> > >>
> > >>     _wrap_it._varnames = _pytest.core.varnames(f)
> > >>     return _wrap_it
> > >>
> > >> and apply it straight to the test function.
> > >>
> > >> After examining the source code I even expected it to just work
> > >> (magically of course) but it didn't.
> > >> Do you think it is worthwhile? If so I can enter a feature request.
> > >>
> > >> Thanks,
> > >> Vyacheslav
> > >> _______________________________________________
> > >> py-dev mailing list
> > >> py-dev at codespeak.net
> > >> http://codespeak.net/mailman/listinfo/py-dev
> > >
> > >
> 



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