1 files changed, 21 insertions, 0 deletions
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 4fe74bf..91f525d 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -10,6 +10,7 @@ import os
 import errno
 import tempfile
 import time
+import traceback
 import selectors
 import sysconfig
 import select
@@ -1557,6 +1558,26 @@ class RunFuncTestCase(BaseTestCase):
         self.assertIn('stderr', c.exception.args[0])
         self.assertIn('capture_output', c.exception.args[0])
 
+    # This test _might_ wind up a bit fragile on loaded build+test machines
+    # as it depends on the timing with wide enough margins for normal situations
+    # but does assert that it happened "soon enough" to believe the right thing
+    # happened.
+    @unittest.skipIf(mswindows, "requires posix like 'sleep' shell command")
+    def test_run_with_shell_timeout_and_capture_output(self):
+        """Output capturing after a timeout mustn't hang forever on open filehandles."""
+        before_secs = time.monotonic()
+        try:
+            subprocess.run('sleep 3', shell=True, timeout=0.1,
+                           capture_output=True)  # New session unspecified.
+        except subprocess.TimeoutExpired as exc:
+            after_secs = time.monotonic()
+            stacks = traceback.format_exc()  # assertRaises doesn't give this.
+        else:
+            self.fail("TimeoutExpired not raised.")
+        self.assertLess(after_secs - before_secs, 1.5,
+                        msg="TimeoutExpired was delayed! Bad traceback:\n```\n"
+                        f"{stacks}```")
+
 
 @unittest.skipIf(mswindows, "POSIX specific tests")
 class POSIXProcessTestCase(BaseTestCase):