Run test_shutdown_with_sys_exit_at_pickle many times

Author: ogrisel

tests/_test_process_executor.py

@@ -112,8 +112,9 @@ def test_shutdown_with_pickle_error(self):
 
     def test_shutdown_with_sys_exit_at_pickle(self):
         self.executor.shutdown()
-        with self.executor_type(max_workers=4) as e:
-            e.submit(id, ExitAtPickle())
+        for i in range(30):
+            with self.executor_type(max_workers=4) as e:
+                e.submit(id, ExitAtPickle())
 
     def test_interpreter_shutdown(self):
         # Free resources to avoid random timeout in CI