[fix] add type annotation in test script

Author: Irfnfnkemed

tests/python/serve/server/test_server_structural_tag.py

@@ -11,7 +11,7 @@
 import json
 import os
 import re
-from typing import Dict, List, Optional
+from typing import Dict, List, Optional, Any
 
 import pytest
 import requests
@@ -136,7 +136,11 @@ def check_openai_stream_response(
 
 
 def check_format(name_beg: str, name_end: str, beg_tag: str, schema: str):
-    schema = json.loads(schema)
+    try:
+        schema: dict[str, Any] = json.loads(schema)
+    except json.JSONDecodeError as e:
+        print(f"Invalid JSON format: {e}")
+        assert False
     assert "hash_code" in schema
     hash_code = schema["hash_code"]
     assert hash_code in CHECK_INFO