[Python-checkins] bpo-45209: fix `UserWarning: resource_tracker` in test_multiprocessing (GH-28377)

[ambv]

https://github.com/python/cpython/commit/f604cf1c377a7648e0686044e6e49900bfc9feef
commit: f604cf1c377a7648e0686044e6e49900bfc9feef
branch: main
author: Nikita Sobolev <mail at sobolevn.me>
committer: ambv <lukasz at langa.pl>
date: 2021-09-21T19:49:42+02:00
summary:

bpo-45209: fix `UserWarning: resource_tracker` in test_multiprocessing (GH-28377)

files:
A Misc/NEWS.d/next/Tests/2021-09-15-23-32-39.bpo-45209.55ntL5.rst
M Lib/test/_test_multiprocessing.py

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 8ebcd0d64dfaa..125e8906d8abc 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -4178,6 +4178,13 @@ def test_shared_memory_cleaned_after_process_termination(self):
                                      " a process was abruptly terminated.")
 
             if os.name == 'posix':
+                # Without this line it was raising warnings like:
+                #   UserWarning: resource_tracker:
+                #   There appear to be 1 leaked shared_memory
+                #   objects to clean up at shutdown
+                # See: https://bugs.python.org/issue45209
+                resource_tracker.unregister(f"/{name}", "shared_memory")
+
                 # A warning was emitted by the subprocess' own
                 # resource_tracker (on Windows, shared memory segments
                 # are released automatically by the OS).
diff --git a/Misc/NEWS.d/next/Tests/2021-09-15-23-32-39.bpo-45209.55ntL5.rst b/Misc/NEWS.d/next/Tests/2021-09-15-23-32-39.bpo-45209.55ntL5.rst
new file mode 100644
index 0000000000000..4c3bed0983b89
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2021-09-15-23-32-39.bpo-45209.55ntL5.rst
@@ -0,0 +1,2 @@
+Fix ``UserWarning: resource_tracker`` warning in
+``_test_multiprocessing._TestSharedMemory.test_shared_memory_cleaned_after_process_termination``