TST: fix unit tests

unittests/test_server_side_scripting.py

@@ -46,7 +46,7 @@ def setup_module():
         content_type = kwargs["headers"]["Content-Type"]
 
         if content_type.startswith("multipart/form-data; boundary"):
-            parts = kwargs["body"]
+            parts = kwargs["body"].multipart_yielder
             stdout = []
             for part in parts:
                 if hasattr(part, "decode"):