Re: master 8dcb19f 4/4: Add a unit test testing interaction between threads and processes.

[Philipp]

> Am 28.02.2021 um 19:36 schrieb Stefan Monnier <monnier@iro.umontreal.ca>:
> 
>>> But set-process-thread accepts a thread argument, so you could bind
>>> the process to a particular thread, couldn't you?
>> Yes, but the threads that call `accept-process-output’ and
>> `process-send-eof’ are different threads; binding the process object to one
>> of the threads would cause the other call to fail.
> 
> IIRC `set-process-thread` determines the thread in which the process
> filters and sentinels are run.  You can still call
> `accept-process-output’ and `process-send-eof’ from other threads.

Partially yes.  It's not possible to call `accept-process-output' from other 
threads than the locked one, if there's one.
So we could change the test to lock each process to the thread that calls 
`accept-process-output'.  I'm fine either way, it shouldn't change the behavior 
of the test.