[TIP] pytest, multiprocessing and pyzmq's ioloop

Pere Martir pere.martir4 at gmail.com
Tue Oct 25 13:45:23 PDT 2011

On Tue, Oct 25, 2011 at 2:34 PM, Stefan Scherfke
<stefan.scherfke at offis.de> wrote:
> If no exceptions occurs, everything runs fine. However, if the
> `multiprocessing.Process` raises an exception and thus never sends a reply,
> py.test waits forever without noticing the exception. The only thing I can
> do about this is to run py.test with "-s" so that I can see exception's
> traceback in the captured stderr and can then abort pytest using Ctrl+C.

I have a similar problem but no better solution yet. It's already
known that py.test simply doesn't catch the exception in the other


You may be interested in the workaround posted on August of 2009 here:


I've not tried it yet. What's your opinion ? Does it workaround also
work for threading2, greenlet, etc ?

I would probably give Twisted Trial a shoot:


According to this recent post, it's said that your application doesn't
has to be a Twisted one to use Trial:


I have not tried it yet neither.

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