bpo-38546: Fix concurrent.futures test_ressources_gced_in_workers() (pythonGH-17652)

vstinner · miss-islington · commit d6d038088020 · 2019-12-18T14:50:29.000Z
Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly stop the manager to prevent leaking a child process running in the background after the test completes. (cherry picked from commit 673c393) Co-authored-by: Victor Stinner <vstinner@python.org>
diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py
@@ -87,8 +87,7 @@ def my_method(self):
 
 
 class EventfulGCObj():
-    def __init__(self, ctx):
-        mgr = get_context(ctx).Manager()
+    def __init__(self, mgr):
         self.event = mgr.Event()
 
     def __del__(self):
@@ -848,12 +847,21 @@ def test_traceback(self):
     def test_ressources_gced_in_workers(self):
         # Ensure that argument for a job are correctly gc-ed after the job
         # is finished
-        obj = EventfulGCObj(self.ctx)
+        mgr = get_context(self.ctx).Manager()
+        obj = EventfulGCObj(mgr)
         future = self.executor.submit(id, obj)
         future.result()
 
         self.assertTrue(obj.event.wait(timeout=1))
 
+        # explicitly destroy the object to ensure that EventfulGCObj.__del__()
+        # is called while manager is still running.
+        obj = None
+        support.gc_collect()
+
+        mgr.shutdown()
+        mgr.join()
+
 
 create_executor_tests(ProcessPoolExecutorTest,
                       executor_mixins=(ProcessPoolForkMixin,
diff --git a/Misc/NEWS.d/next/Tests/2019-12-18-14-52-08.bpo-38546.2kxNuM.rst b/Misc/NEWS.d/next/Tests/2019-12-18-14-52-08.bpo-38546.2kxNuM.rst
@@ -0,0 +1,3 @@
+Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly
+stop the manager to prevent leaking a child process running in the background
+after the test completes.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+Fix test_ressources_gced_in_workers() of test_concurrent_futures: explicitly`
	`2`	`+stop the manager to prevent leaking a child process running in the background`
	`3`	`+after the test completes.`