bpo-38546: multiprocessing tests stop the resource tracker (GH-17641) (…

…GH-17647)

Multiprocessing and concurrent.futures tests now stop the resource
tracker process when tests complete.

Add ResourceTracker._stop() method to
multiprocessing.resource_tracker.

Add _cleanup_tests() helper function to multiprocessing.util: share
code between multiprocessing and concurrent.futures tests.

(cherry picked from commit 9707e8e)
(cherry picked from commit 35acb35)

Lib/multiprocessing/util.py

@@ -456,3 +456,24 @@ def spawnv_passfds(path, args, passfds):
     finally:
         os.close(errpipe_read)
         os.close(errpipe_write)
+
+
+def _cleanup_tests():
+    """Cleanup multiprocessing resources when multiprocessing tests
+    completed."""
+
+    from test import support
+
+    # cleanup multiprocessing
+    process._cleanup()
+
+    # Stop the ForkServer process if it's running
+    from multiprocessing import forkserver
+    forkserver._forkserver._stop()
+
+    # bpo-37421: Explicitly call _run_finalizers() to remove immediately
+    # temporary directories created by multiprocessing.util.get_temp_dir().
+    _run_finalizers()
+    support.gc_collect()
+
+    support.reap_children()

Lib/test/_test_multiprocessing.py

@@ -5050,17 +5050,7 @@ def tearDownModule():
         if need_sleep:
             time.sleep(0.5)
 
-        multiprocessing.process._cleanup()
-
-        # Stop the ForkServer process if it's running
-        from multiprocessing import forkserver
-        forkserver._forkserver._stop()
-
-        # bpo-37421: Explicitly call _run_finalizers() to remove immediately
-        # temporary directories created by multiprocessing.util.get_temp_dir().
-        multiprocessing.util._run_finalizers()
-
-        test.support.gc_collect()
+        multiprocessing.util._cleanup_tests()
 
     remote_globs['setUpModule'] = setUpModule
     remote_globs['tearDownModule'] = tearDownModule

Lib/test/test_concurrent_futures.py

@@ -26,6 +26,7 @@
     BrokenExecutor)
 from concurrent.futures.process import BrokenProcessPool
 from multiprocessing import get_context
+import multiprocessing.util
 
 
 def create_future(state=PENDING, exception=None, result=None):
@@ -1253,6 +1254,7 @@ def test_main():
         test.support.run_unittest(__name__)
     finally:
         test.support.reap_children()
+        multiprocessing.util._cleanup_tests()
 
 if __name__ == "__main__":
     test_main()

Misc/NEWS.d/next/Tests/2019-12-17-15-27-07.bpo-38546.82JwN2.rst

@@ -0,0 +1,2 @@
+Multiprocessing and concurrent.futures tests now stop the resource tracker
+process when tests complete.