diff --git a/libs/partners/mongodb/tests/utils.py b/libs/partners/mongodb/tests/utils.py
index 674bd2c43fd0e..d62b2025f48ea 100644
--- a/libs/partners/mongodb/tests/utils.py
+++ b/libs/partners/mongodb/tests/utils.py
@@ -17,7 +17,7 @@
     BaseMessage,
 )
 from langchain_core.outputs import ChatGeneration, ChatResult
-from pydantic import validator
+from pydantic import model_validator
 from pymongo.collection import Collection
 from pymongo.results import DeleteResult, InsertManyResult
 
@@ -134,15 +134,14 @@ class FakeLLM(LLM):
     sequential_responses: Optional[bool] = False
     response_index: int = 0
 
-    @validator("queries", always=True)
-    def check_queries_required(
-        cls, queries: Optional[Mapping], values: Mapping[str, Any]
-    ) -> Optional[Mapping]:
-        if values.get("sequential_response") and not queries:
+    @model_validator(mode="before")
+    @classmethod
+    def check_queries_required(cls, values: dict) -> dict:
+        if values.get("sequential_response") and not values.get("queries"):
             raise ValueError(
                 "queries is required when sequential_response is set to True"
             )
-        return queries
+        return values
 
     def get_num_tokens(self, text: str) -> int:
         """Return number of tokens."""