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Implementing an idea from Guido on the checkins list:

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When regrtest.py finds an attribute "test_main" in a test it imports,
regrtest runs the test's test_main after the import.  test_threaded_import
needs this else the cross-thread import lock prevents it from making
progress.  Other tests can use this hack too, but I doubt it will ever be
popular.
This commit is contained in:
Tim Peters 2001-05-22 18:28:25 +00:00
parent bc5619826e
commit d97422115e
2 changed files with 25 additions and 24 deletions
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40
Lib/test/test_threaded_import.py
View file

@ -6,6 +6,7 @@
# randrange, and then Python hangs.
import thread
from test_support import verbose
critical_section = thread.allocate_lock()
done = thread.allocate_lock()
@ -20,33 +21,26 @@ def task():
done.release()
critical_section.release()
# Tricky, tricky, tricky.
# When regrtest imports this module, the thread running regrtest grabs the
# import lock and won't let go of it until this module returns. All other
# threads attempting an import hang for the duration. So we have to spawn
# a thread to run the test and return to regrtest.py right away, else the
# test can't make progress.
#
# One miserable consequence: This test can't wait to make sure all the
# threads complete!
#
# Another: If this test fails, the output may show up while running
# some other test.
#
# Another: If you run this test directly, the OS will probably kill
# all the threads right away, because the program exits immediately
# after spawning a thread to run the real test.
#
# Another: If this test ever does fail and you attempt to run it by
# itself via regrtest, the same applies: regrtest will get out so fast
# the OS will kill all the threads here.
# Tricky: When regrtest imports this module, the thread running regrtest
# grabs the import lock and won't let go of it until this module returns.
# All other threads attempting an import hang for the duration. Since
# this test spawns threads that do little *but* import, we can't do that
# successfully until after this module finishes importing and regrtest
# regains control. To make this work, a special case was added to
# regrtest to invoke a module's "test_main" function (if any) after
# importing it.
def run_the_test():
def test_main(): # magic name! see above
global N, done
done.acquire()
for N in [1, 2, 3, 4, 20, 4, 3, 2]:
for N in (20, 50) * 3:
if verbose:
print "Trying", N, "threads ...",
for i in range(N):
thread.start_new_thread(task, ())
done.acquire()
if verbose:
print "OK."
thread.start_new_thread(run_the_test, ())
if __name__ == "__main__":
test_main()