diff --git a/libs/langchain/tests/unit_tests/chat_models/test_base.py b/libs/langchain/tests/unit_tests/chat_models/test_base.py
index 65be8a429f2..611f251b816 100644
--- a/libs/langchain/tests/unit_tests/chat_models/test_base.py
+++ b/libs/langchain/tests/unit_tests/chat_models/test_base.py
@@ -270,6 +270,7 @@ def test_configurable_with_default() -> None:
             "max_retries": 2,
             "stop_sequences": None,
             "anthropic_api_url": "https://api.anthropic.com",
+            "anthropic_proxy": None,
             "anthropic_api_key": SecretStr("bar"),
             "betas": None,
             "default_headers": None,