[erlang-questions] Testing gen_statem timers

[Raimo Niskanen]

On Thu, Aug 15, 2019 at 06:44:43PM +0200, Torben Hoffmann wrote:
> Hi Micael,
> 
> I'm very biassed here, but apart from my creator fondness many of my
> colleagues are very happy about the approach that my Chronos library takes
> when it comes to timers.
> 
> https://github.com/lehoff/chronos

I notice that in that README.md you compare Chronos with the timeout feature
in gen_server and gen_fsm.  The timers in gen_statem were specifically
designed to remedy most of their shortcomings.

So, from a usability point of view, can you elaborate what Cronos
can do better than gen_statem timers?

> 
> Basically, don't use the internal timers, but do read the full README from
> Chronos.
> 
> Very happy to assist you and improve anything in Chronos, if you find it
> confusing.
> 
> Cheers,
> Torben
> 
> On Thu, 15 Aug 2019 at 13:35, Micael Nussbaumer <micaelnussbaumer@REDACTED>
> wrote:
> 
> > Hi, first time poster (but I've read many threads in here).
> >
> > How does one usually test gen_statem internal timer events?
> > Usually you test the effects of the behaviour somehow, and I can test
> > that. But in this particular case I had a situation where timers with uniq
> > references are created, later on they usually get removed and all is fine -
> > they're created for each extra worker started and at some point the worker
> > is removed by the timer event that trigger checking some conditions.
> >
> > I noticed after that, the way I had written it, if an extra worker was
> > started then died for some other reason than the timer event taking it out,
> > I could theoretically accumulate timers that wouldn't be removed, I've
> > since then corrected that but still I have no tests ensuring me that it
> > actually works.
> > So my question is if there's any even way to test it (even if with
> > tracing)?
> > Thanks
> >
> > *M*icael *N*ussbaumer
> > artistic portfolio <http://cargocollective.com/micaelnussbaumer>
> >
> 
> 
> -- 
> http://www.linkedin.com/in/torbenhoffmann
> @LeHoff


-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB