Stresstests: envvar C_SLEEP can now be used to add tracebacks to sleep calls

funtests/stress/stress/__init__.py

@@ -1,4 +1,19 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import
 
+import os
+import time
+
+if os.environ.get('C_SLEEP'):
+
+    _orig_sleep = time.sleep
+
+    def _sleep(n):
+        print('WARNING: Time sleep for {0}s'.format(n))
+        import traceback
+        traceback.print_stack()
+        _orig_sleep(n)
+    time.sleep = _sleep
+
+
 from .app import app  # noqa