diff --git a/comfy/component_model/folder_path_types.py b/comfy/component_model/folder_path_types.py
index 91aec66e2..56486bc8b 100644
--- a/comfy/component_model/folder_path_types.py
+++ b/comfy/component_model/folder_path_types.py
@@ -102,7 +102,7 @@ class PathsList:
         paths = [x for x in self]
         return paths[item]
 
-    def append(self, path_str: str):
+    def append(self, path_str: str | Path):
         p: FolderNames = self.parent()
         p.add_paths(self.folder_name, [path_str])
 
diff --git a/tests/unit/app_test/model_manager_test.py b/tests/unit/app_test/model_manager_test.py
index f25bbf6e8..fe7d4114c 100644
--- a/tests/unit/app_test/model_manager_test.py
+++ b/tests/unit/app_test/model_manager_test.py
@@ -1,22 +1,26 @@
-import pytest
 import base64
 import json
 import struct
 from io import BytesIO
+
+import pytest
 from PIL import Image
 from aiohttp import web
-from unittest.mock import patch
 
 from comfy.app.model_manager import ModelFileManager
+from comfy.component_model.folder_path_types import FolderNames
+from comfy.execution_context import context_folder_names_and_paths
 
 pytestmark = (
     pytest.mark.asyncio
 )  # This applies the asyncio mark to all test functions in the module
 
+
 @pytest.fixture
 def model_manager():
     return ModelFileManager()
 
+
 @pytest.fixture
 def app(model_manager):
     app = web.Application()
@@ -25,6 +29,7 @@ def app(model_manager):
     app.add_routes(routes)
     return app
 
+
 async def test_get_model_preview_safetensors(aiohttp_client, app, tmp_path):
     img = Image.new('RGB', (100, 100), 'white')
     img_byte_arr = BytesIO()
@@ -43,9 +48,12 @@ async def test_get_model_preview_safetensors(aiohttp_client, app, tmp_path):
         f.write(length_bytes)
         f.write(header_bytes)
 
-    with patch('folder_paths.folder_names_and_paths', {
-        'test_folder': ([str(tmp_path)], None)
-    }):
+    fn = FolderNames()
+    with context_folder_names_and_paths(fn):
+        test_folder = fn["test_folder"]
+        test_folder.paths.append(tmp_path)
+        test_folder.supported_extensions |= {".safetensors"}
+
         client = await aiohttp_client(app)
         response = await client.get('/experiment/models/preview/test_folder/0/test_model.safetensors')