From 6fcbb3473eb26d6dc6d00021d1095b8fca8c3aa8 Mon Sep 17 00:00:00 2001
From: Ihar Hrachyshka <ihar.hrachyshka@gmail.com>
Date: Mon, 4 May 2026 19:50:54 -0400
Subject: [PATCH] tests: Gracefully handle missing set_device for mps

mps backend doesn't have set_device, so if mps is available on test run,
the test fails with:

AttributeError: <module 'torch.mps' from
'[...]/site-packages/torch/mps/__init__.py'> does not have the attribute
'set_device'
---
 tests/test_accelerator.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/test_accelerator.py b/tests/test_accelerator.py
index ebab8a8c057..6ac346c0cc6 100644
--- a/tests/test_accelerator.py
+++ b/tests/test_accelerator.py
@@ -259,7 +259,9 @@ def noop(*args, **kwargs):
             pass
 
         with (
-            patch(f"torch.{torch_device}.set_device", noop),
+            # Some backends such as MPS do not expose a module-level `set_device`.
+            # This test only exercises env var parsing, so a synthetic attribute is enough.
+            patch(f"torch.{torch_device}.set_device", noop, create=True),
             patch_environment(ACCELERATE_TORCH_DEVICE=f"{torch_device}:64"),
         ):
             accelerator = Accelerator()