diff --git a/tests/conftest.py b/tests/conftest.py
index bf684f69..1ee41a5b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -33,6 +33,7 @@ for _mod in [
     "sentence_transformers",
     "swarm",
     "swarm.event_log",
+    "cv2",  # OpenCV import can hang under pytest-xdist parallel workers
 ]:
     sys.modules.setdefault(_mod, MagicMock())