Antoine: I told you that such stess-test is going to require work to polish it. So here is another example of failure. Enjoy :-)

http://buildbot.python.org/all/builders/AMD64%20Debian%20root%203.6/builds/534/steps/test/logs/stdio


== CPython 3.6.2rc1+ (heads/3.6:580cd5c, Jul 5 2017, 00:47:42) [GCC 4.9.2]
== Linux-3.16.0-4-amd64-x86_64-with-debian-8.7 little-endian
...
== CPU count: 1
...
Run tests in parallel using 2 child processes
0:11:40 load avg: 1.29 [383/405/1] test_signal failed -- running: test_datetime (38 sec)
...
======================================================================
FAIL: test_stress_delivery_dependent (test.test_signal.StressTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/buildarea/3.6.angelico-debian-amd64/build/Lib/test/test_signal.py", line 1053, in test_stress_delivery_dependent
    self.assertEqual(len(sigs), N, "Some signals were lost")
AssertionError: 4602 != 10000 : Some signals were lost

======================================================================
FAIL: test_stress_delivery_simultaneous (test.test_signal.StressTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/root/buildarea/3.6.angelico-debian-amd64/build/Lib/test/test_signal.py", line 1086, in test_stress_delivery_simultaneous
    self.assertEqual(len(sigs), N, "Some signals were lost")
AssertionError: 8206 != 10000 : Some signals were lost