[tests] add tests for combining layerwise upcasting and groupoffloading. (#11558)

* add tests for combining layerwise upcasting and groupoffloading.

* feedback

tests/models/test_modeling_common.py

@@ -1580,6 +1580,34 @@ class ModelTesterMixin:
         self.assertTrue(torch.allclose(output_without_group_offloading, output_with_group_offloading3, atol=1e-5))
         self.assertTrue(torch.allclose(output_without_group_offloading, output_with_group_offloading4, atol=1e-5))
 
+    @parameterized.expand([(False, "block_level"), (True, "leaf_level")])
+    @require_torch_accelerator
+    @torch.no_grad()
+    def test_group_offloading_with_layerwise_casting(self, record_stream, offload_type):
+        torch.manual_seed(0)
+        init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
+        model = self.model_class(**init_dict)
+
+        if not getattr(model, "_supports_group_offloading", True):
+            return
+
+        model.to(torch_device)
+        model.eval()
+        _ = model(**inputs_dict)[0]
+
+        torch.manual_seed(0)
+        init_dict, inputs_dict = self.prepare_init_args_and_inputs_for_common()
+        storage_dtype, compute_dtype = torch.float16, torch.float32
+        inputs_dict = cast_maybe_tensor_dtype(inputs_dict, torch.float32, compute_dtype)
+        model = self.model_class(**init_dict)
+        model.eval()
+        additional_kwargs = {} if offload_type == "leaf_level" else {"num_blocks_per_group": 1}
+        model.enable_group_offload(
+            torch_device, offload_type=offload_type, use_stream=True, record_stream=record_stream, **additional_kwargs
+        )
+        model.enable_layerwise_casting(storage_dtype=storage_dtype, compute_dtype=compute_dtype)
+        _ = model(**inputs_dict)[0]
+
     def test_auto_model(self, expected_max_diff=5e-5):
         if self.forward_requires_fresh_args:
             model = self.model_class(**self.init_dict)