Identify why test_mp_checkout is failing and how to fix it

[satelliteqe]

Identify why test_mp_checkout is failing and how to fix it

[jarovo]

The process child processes are zombies:

jhenner  3347498  3.2  0.5 296956 42672 pts/1    S    01:50   0:00 /home/jhenner/work/sat/broker/venv/bin/python venv/bin/py.test tests -v
jhenner  3347507  0.0  0.0      0     0 pts/1    Z    01:50   0:00 [py.test] <defunct>
jhenner  3347508  0.0  0.0      0     0 pts/1    Z    01:50   0:00 [py.test] <defunct>

The parent hangs when dealing with the Queue

(gdb) py-bt
Traceback (most recent call first):
  <built-in method read of module object at remote 0x7fd1114b9680>
  File "/usr/lib64/python3.9/multiprocessing/connection.py", line 384, in _recv
    chunk = read(handle, remaining)
  File "/usr/lib64/python3.9/multiprocessing/connection.py", line 419, in _recv_bytes
    buf = self._recv(4)
  File "/usr/lib64/python3.9/multiprocessing/connection.py", line 221, in recv_bytes
    buf = self._recv_bytes(maxlength)
  File "/usr/lib64/python3.9/multiprocessing/queues.py", line 103, in get
    res = self._recv_bytes()
  File "/home/jhenner/work/sat/broker/broker/broker.py", line 75, in _mp_split
    result.append(mp_queue.get())
  File "/home/jhenner/work/sat/broker/broker/broker.py", line 27, in wrapper
    return vmb_inst._mp_split(vmb_inst.checkout, count, **vmb_inst._kwargs)
  File "/home/jhenner/work/sat/broker/tests/test_broker.py", line 50, in test_mp_checkout

I started an attempt #53 to fix this using the concurrent.futures which I find easy to use and enough for many situations.