python: fix non-determinism in the test suite.
Some tests calling spot.automaton('non-existing|') where failing either with a "process returned 127", or, under heavier load, with "failed to read from...". The latter occur if we poll() the exit status before the children has had the tame to finish. * wrap/python/spot.py: Make sure we wait for the child process if we reach EOF, so that we can report the error status. * wrap/python/tests/automata-io.ipynb, wrap/python/tests/piperead.ipynb: Update.
Showing with 55 additions and 43 deletions