[tests] ensure device-required software is available in the testing environment before testing (#29477)

* gix

* fix style

* add warning

* revert

* no newline

* revert

* revert

* add CUDA as well

src/transformers/testing_utils.py

@@ -808,6 +808,19 @@ if is_torch_available():
 
     if "TRANSFORMERS_TEST_DEVICE" in os.environ:
         torch_device = os.environ["TRANSFORMERS_TEST_DEVICE"]
+        if torch_device == "cuda" and not torch.cuda.is_available():
+            raise ValueError(
+                f"TRANSFORMERS_TEST_DEVICE={torch_device}, but CUDA is unavailable. Please double-check your testing environment."
+            )
+        if torch_device == "xpu" and not is_torch_xpu_available():
+            raise ValueError(
+                f"TRANSFORMERS_TEST_DEVICE={torch_device}, but XPU is unavailable. Please double-check your testing environment."
+            )
+        if torch_device == "npu" and not is_torch_npu_available():
+            raise ValueError(
+                f"TRANSFORMERS_TEST_DEVICE={torch_device}, but NPU is unavailable. Please double-check your testing environment."
+            )
+
         try:
             # try creating device to see if provided device is valid
             _ = torch.device(torch_device)