use correct separator.

spiffworkflow-backend/src/spiffworkflow_backend/services/file_system_service.py

@@ -31,10 +31,17 @@ class FileSystemService:
         app_root = current_app.root_path
         return os.path.join(app_root, "..", dir_name)
 
+    @staticmethod
+    def id_string_to_relative_path(id_string):
+        return id_string.replace("/", os.sep)
+
     @staticmethod
     def process_group_path(name: str) -> str:
         """Category_path."""
-        return os.path.abspath(os.path.join(FileSystemService.root_path(), name))
+        return os.path.abspath(os.path.join(
+            FileSystemService.root_path(),
+            FileSystemService.id_string_to_relative_path(name)
+        ))
 
     @staticmethod
     def full_path_from_relative_path(relative_path: str) -> str:

spiffworkflow-backend/src/spiffworkflow_backend/services/process_model_service.py

@@ -207,7 +207,10 @@ class ProcessModelService(FileSystemService):
         """Look for a given process_group, and return it."""
         if os.path.exists(FileSystemService.root_path()):
             process_group_path = os.path.abspath(
-                os.path.join(FileSystemService.root_path(), process_group_id)
+                os.path.join(
+                    FileSystemService.root_path(),
+                    FileSystemService.id_string_to_relative_path(process_group_id)
+                )
             )
             if self.is_group(process_group_path):
                 return self.__scan_process_group(process_group_path)

spiffworkflow-backend/tests/spiffworkflow_backend/integration/test_process_api.py

@@ -2384,7 +2384,7 @@ class TestProcessApi(BaseTest):
         for group in groups:
             persisted = ProcessModelService().get_process_group(group)
             assert persisted is not None
-            assert persisted.id_for_file_path() == group
+            assert persisted.id == group
 
     def test_move_model(
         self,