device agnostic models testing (#27146)

* device agnostic models testing

* add decorator `require_torch_fp16`

* make style

* apply review suggestion

* Oops, the fp16 decorator was misused

tests/models/mistral/test_modeling_mistral.py

@@ -22,7 +22,14 @@ import unittest
 from pytest import mark
 
 from transformers import AutoTokenizer, MistralConfig, is_torch_available
-from transformers.testing_utils import require_flash_attn, require_torch, require_torch_gpu, slow, torch_device
+from transformers.testing_utils import (
+    backend_empty_cache,
+    require_flash_attn,
+    require_torch,
+    require_torch_gpu,
+    slow,
+    torch_device,
+)
 
 from ...generation.test_utils import GenerationTesterMixin
 from ...test_configuration_common import ConfigTester
@@ -450,7 +457,7 @@ class MistralIntegrationTest(unittest.TestCase):
         torch.testing.assert_close(out[0, 0, :30], EXPECTED_SLICE, atol=1e-4, rtol=1e-4)
 
         del model
-        torch.cuda.empty_cache()
+        backend_empty_cache(torch_device)
         gc.collect()
 
     @slow
@@ -467,5 +474,5 @@ class MistralIntegrationTest(unittest.TestCase):
         self.assertEqual(EXPECTED_TEXT_COMPLETION, text)
 
         del model
-        torch.cuda.empty_cache()
+        backend_empty_cache(torch_device)
         gc.collect()