Dump thread stacks on SIGUSR1 when running tests to troubleshoot

deadlocks and similar.

Author: hategan

tests/conftest.py

@@ -8,11 +8,13 @@
 import re
 import secrets
 import shutil
+import signal
 import socket
 import subprocess
 import sys
 import threading
 import time
+import traceback
 from functools import partial
 from pathlib import Path
 from typing import Dict, List, Optional
@@ -76,6 +78,22 @@ def pytest_addoption(parser):
                           'is uploaded to the test aggregation server. ')
 
 
+def debug(sig, frame):
+    with open('/tmp/python-dump.txt', 'w') as f:
+        f.write('Test')
+        try:
+            for thr in threading.enumerate():
+                f.write(str(thr))
+                f.write('\n')
+                traceback.print_stack(sys._current_frames()[thr.ident], file=f)
+                f.write('\n\n')
+        except Exception as ex:
+            f.write(str(ex))
+
+
+signal.signal(signal.SIGUSR1, debug)  # Register handler
+
+
 def _get_executors(config: Dict[str, str]) -> List[str]:
     execs_str = config.getoption('executors')
     execs = execs_str.split(',')