bpo-38614: Use test.support.SHORT_TIMEOUT constant (GH-17566)

Replace hardcoded timeout constants in tests with SHORT_TIMEOUT of
test.support, so it's easier to ajdust this timeout for all tests at
once.

SHORT_TIMEOUT is 30 seconds by default, but it can be longer
depending on --timeout command line option.

The change makes almost all timeouts longer, except
test_reap_children() of test_support which is made 2x shorter:
SHORT_TIMEOUT should be enough. If this test starts to fail,
LONG_TIMEOUT should be used instead.

Uniformize also "from test import support" import in some test files.

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 7c16974..62f2d54 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -265,7 +265,7 @@ class ThreadTests(BaseTestCase):
         self.assertEqual(result, 1) # one thread state modified
         if verbose:
             print("    waiting for worker to say it caught the exception")
-        worker_saw_exception.wait(timeout=10)
+        worker_saw_exception.wait(timeout=support.SHORT_TIMEOUT)
         self.assertTrue(t.finished)
         if verbose:
             print("    all OK -- joining worker")
@@ -640,7 +640,7 @@ class ThreadTests(BaseTestCase):
         finish.release()
         # When the thread ends, the state_lock can be successfully
         # acquired.
-        self.assertTrue(tstate_lock.acquire(timeout=5), False)
+        self.assertTrue(tstate_lock.acquire(timeout=support.SHORT_TIMEOUT), False)
         # But is_alive() is still True:  we hold _tstate_lock now, which
         # prevents is_alive() from knowing the thread's end-of-life C code
         # is done.