* Use try/except ImportError or test_support.import_module() to import thread
and threading modules
* Add @unittest.skipUnless(threading, ...) to testcases using threads
appears to be utterly insane. Plug some theoretical
insecurities in the test script:
- Verify that the SIGALRM handler was actually installed.
- Don't call alarm() before the handler is installed.
- Move everything that can fail inside the try/finally,
so the test cleans up after itself more often.
- Try sending all the expected signals in
force_test_exit(), not just SIGALRM. Since that was
fixed to actually send SIGALRM (instead of invisibly
dying with an AttributeError), we've seen that sending
SIGALRM alone does not stop this from hanging.
- Move the "kill the child" business into the finally
clause, so the child doesn't survive test failure
to send SIGALRM to other tests later (there are also
baffling SIGALRM-related failures in test_socket).
- Cancel the alarm in the finally clause -- if the
test dies early, we again don't want SIGALRM showing
up to confuse a later test.
Alas, this still relies on timing luck wrt the spawned
script that sends the test signals, but it's hard to see
how waiting for seconds can so often be so unlucky.
test_threadedsignals: curiously, this test never fails
on Tru64, but doesn't normally signal SIGALRM. Anyway,
fixed an obvious (but probably inconsequential) logic
error.
Florent Xicluna
Victor Stinner
Ezio Melotti
Senthil Kumaran
Benjamin Peterson
Tim Peters
Fred Drake
Michael W. Hudson