Looks pretty good all around, got some comments though.

1. This doesn't 100% fix give threads a name prefix #1332 does it? It only adds the prefix to worker threads, is there anything preventing us from doing the same with the dispatcher and updater thread?
2. Should it maybe be called ptb:<id>:worker: or telegram:<id>:worker or something like that? Just to make it 100% explicit what the thread is?
3. I'm not really a fan of having a method just for testing purposes. Can't you just do dp._Dispatcher__async_threads in the test?

@jsmnbom I will address your notes later, want to see if this indeed fixes Travis' behavior

I am looking forward for your improvements and will try out asap ...

@Eldinnie any updates on this? Do you agree with my comments? I can implement them if you dont' have time ^ ^

Any updates about this PR? I have the same issue as #1332 ( ._.)

As long as this PR is not accepted into Release 12 I have tricked around with something like this which is not beautiful but does the necessary change:

pretty_thread_names = True
prefix_programname = "YourProgramnameHere"
prefix_worker_thread = "Worker"

# theUpdater contains the telegram Updater Object

if pretty_thread_names:
    try:
        for t in theUpdater._Updater__threads:
          if 'dispatcher' in t.name: 
            t.name = prefix_programname+' Dispatcher'
            
          if 'updater' in t.name: 
            t.name = prefix_programname+' Updater'
            
        for t in theUpdater.dispatcher._Dispatcher__async_threads:
          *_, num = t.name.split('_')
          t.name = '{0} {1} {2}'.format(prefix_programname, prefix_worker_thread, num) if num.isnumeric() else num

    except:
        pass

Renamed all threads and changed base.

@jsmnbom care to take another look?

This mostly looks good now, but i still don't think i can see my comment 3 adressed?

3. I'm not really a fan of having a method just for testing purposes. Can't you just do dp._Dispatcher__async_threads in the test?

No you can't.
It's a protected variable