test: add more unit tests of tools (#315)

* test: add more test on test_tts.py

* test: add unit test of search and retriever in tools

* test: remove the main code of search.py

* test: add the travily_search unit test

* reformate the codes

* test: add unit tests of tools

* Added the pytest-asyncio dependency

* added the license header of test_tavily_search_api_wrapper.py

src/tools/tavily_search/tavily_search_results_with_images.py

@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import json
 from typing import Dict, List, Optional, Tuple, Union