Output of attached test case:

non-existing indeed
subprocess-exec-test.py:11: ResourceWarning: unclosed <socket.socket fd=6, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
  print("non-existing indeed")
ResourceWarning: Enable tracemalloc to get the object allocation traceback
subprocess-exec-test.py:11: ResourceWarning: unclosed <socket.socket fd=7, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0>
  print("non-existing indeed")
ResourceWarning: Enable tracemalloc to get the object allocation traceback
.
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Ran 1 test in 0.007s

OK