Re: Adding a TOR system test - confusing results

[Ludovic Courtès]

Chris Marusich <address@hidden> skribis:

> address@hidden (Ludovic Courtès) writes:
>
>> Chris Marusich <address@hidden> skribis:
>>
>>> Why does it pass?  The (sleep 999999) form appears to be totally
>>> ignored, and I don't understand why.  It's concerning to me that I can't
>>> understand how the code is being executed.  I expected the test to hang.
>>
>> According to the manual (info "(guile) Signals"):
>>
>>  -- Scheme Procedure: sleep secs
>>  -- Scheme Procedure: usleep usecs
>>  -- C Function: scm_sleep (secs)
>>  -- C Function: scm_usleep (usecs)
>>      Wait the given period SECS seconds or USECS microseconds (both
>>      integers).  If a signal arrives the wait stops and the return value
>>      is the time remaining, in seconds or microseconds respectively.  If
>>      the period elapses with no signal the return is zero.
>>
>> So I suspect that the marionette process got a signal, and thus ‘sleep’
>> returned quickly.  Could you print its return value?
>
> Thank you for the reply!  The return value is 999998.  Like you said,
> maybe it's possible that the marionette process got a signal.  But why
> would that happen?

I’m not sure!  It could be SIGPIPE or SIGCHLD, this is left as an
exercise to you.  :-)  Seriously, you could register signal handlers and
try to see what’s going on.

It doesn’t change the fact that the return value of ‘sleep’ must be
checked, though.

> I have a related question.  Is there a guarantee that the test case will
> begin after the TOR service has started up?

Most service tests start by waiting for the service to be up using
something like:

            (marionette-eval
             '(begin
                (use-modules (gnu services herd))
                (start-service 'mcron))
             marionette)

That blocks until ‘mcron’ is up or it has failed to start.

HTH!

Ludo’.