The following command fails randomly:

$ ./python -m test test_multiprocessing_fork -R 3:3 -m test.test_multiprocessing_fork.WithProcessesTestHeap.test_heap -v

Run 1:

test_multiprocessing_fork leaked [73, 52, 33] references, sum=158
test_multiprocessing_fork leaked [31, 23, 14] memory blocks, sum=68
test_multiprocessing_fork leaked [2, 0, 0] file descriptors, sum=2
test_multiprocessing_fork failed

Run 2:

1 test OK.

Run 6:

test_multiprocessing_fork leaked [0, 2, 0] file descriptors, sum=2
test_multiprocessing_fork failed