adjust unit tests for `test_save_load_float16` (#12500)

* adjust unit tests for wan pipeline
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

* update code
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

* avoid adjusting common `get_dummy_components` API
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

* use `form_pretrained` to `transformer` and `transformer_2`
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

* update code
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

* update
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>

---------
Signed-off-by: Liu, Kaixuan <kaixuan.liu@intel.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>

tests/pipelines/test_pipelines_common.py

@@ -1422,7 +1422,18 @@ class PipelineTesterMixin:
     def test_save_load_float16(self, expected_max_diff=1e-2):
         components = self.get_dummy_components()
         for name, module in components.items():
-            if hasattr(module, "half"):
+            # Account for components with _keep_in_fp32_modules
+            if hasattr(module, "_keep_in_fp32_modules") and module._keep_in_fp32_modules is not None:
+                for name, param in module.named_parameters():
+                    if any(
+                        module_to_keep_in_fp32 in name.split(".")
+                        for module_to_keep_in_fp32 in module._keep_in_fp32_modules
+                    ):
+                        param.data = param.data.to(torch_device).to(torch.float32)
+                    else:
+                        param.data = param.data.to(torch_device).to(torch.float16)
+
+            elif hasattr(module, "half"):
                 components[name] = module.to(torch_device).half()
 
         pipe = self.pipeline_class(**components)