A child Python writes a piped stderr in the ANSI codepage on Windows, so the
non-ASCII limit value in the usage-error test came back as U+FFFD. The
helper now sets PYTHONIOENCODING=utf-8 for the child.
Review follow-ups: the runner now shows warnings as unittest.main does
(DeprecationWarning and ResourceWarning were hidden), rejects non-ASCII
digit limits with the one-line exit-2 error, and starts each 'start:' line
on its own line at default verbosity. The docs now say that class and module
fixtures count toward the test before them, that the shutdown limit covers
interpreter exit, and that exit 5 on zero tests is 3.12+ behaviour applied
on every version.
tests/run_suite.py discovers the same tests as unittest discover -s tests,
with the same sys.path and exit codes (5 when none ran), writes
'start: <test id>' to stderr before each test and arms
faulthandler.dump_traceback_later: 120 s per test (PM_TEST_HANG_LIMIT) and
120 s after the run (PM_TEST_SHUTDOWN_LIMIT), never cancelled. A hang in a
test, its teardown, its event-loop shutdown or interpreter exit prints every
thread's stack and exits non-zero instead of running to the job limit.
The pre-push hook now runs it too.
Vito Sansevero