chore: import upstream snapshot with attribution

tests/utilities/test_distributed.py

@@ -0,0 +1,27 @@
+# ------------------------------------------------------------------------
+# RF-DETR
+# Copyright (c) 2025 Roboflow. All Rights Reserved.
+# Licensed under the Apache License, Version 2.0 [see LICENSE for details]
+# ------------------------------------------------------------------------
+"""Tests for distributed utility helpers."""
+
+from unittest.mock import patch
+
+from rfdetr.utilities.distributed import all_gather
+
+
+def test_all_gather_supports_cpu_without_tensor_truthiness_error() -> None:
+    """all_gather should work on CPU-only setups and return gathered objects."""
+
+    def _fake_all_gather(output_tensors, input_tensor) -> None:
+        for out in output_tensors:
+            out.copy_(input_tensor)
+
+    with (
+        patch("rfdetr.utilities.distributed.get_world_size", return_value=2),
+        patch("rfdetr.utilities.distributed.dist.all_gather", side_effect=_fake_all_gather),
+        patch("rfdetr.utilities.distributed.torch.cuda.is_available", return_value=False),
+    ):
+        result = all_gather({"value": 7})
+
+    assert result == [{"value": 7}, {"value": 7}]