Issue #11659: Fix ResourceWarning in test_subprocess introduced by #11459.
Patch by Ben Hayden.
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 410849f..837bdb5 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -874,6 +874,7 @@
                                  stdout=subprocess.PIPE,
                                  bufsize=0)
             f = p.stdout
+            self.addCleanup(f.close)
             try:
                 self.assertEqual(f.read(4), b"appl")
                 self.assertIn(f, select.select([f], [], [], 0.0)[0])