fix(standard-tests): ensure non-negative token counts in usage metadata assertions (#32593)

Author: mdrxy

libs/standard-tests/langchain_tests/integration_tests/chat_models.py

@@ -1098,26 +1098,36 @@ def supported_usage_metadata_details(self) -> dict:
             )
         if "cache_read_input" in self.supported_usage_metadata_details["invoke"]:
             msg = self.invoke_with_cache_read_input()
-            assert (usage_metadata := msg.usage_metadata) is not None
-            assert (
-                input_token_details := usage_metadata.get("input_token_details")
-            ) is not None
-            assert isinstance(input_token_details.get("cache_read"), int)
+            usage_metadata = msg.usage_metadata
+            assert usage_metadata is not None
+            input_token_details = usage_metadata.get("input_token_details")
+            assert input_token_details is not None
+            cache_read_tokens = input_token_details.get("cache_read")
+            assert isinstance(cache_read_tokens, int)
+            assert cache_read_tokens >= 0
             # Asserts that total input tokens are at least the sum of the token counts
-            assert usage_metadata.get("input_tokens", 0) >= sum(
-                v for v in input_token_details.values() if isinstance(v, int)
+            total_detailed_tokens = sum(
+                v for v in input_token_details.values() if isinstance(v, int) and v >= 0
             )
+            input_tokens = usage_metadata.get("input_tokens", 0)
+            assert isinstance(input_tokens, int)
+            assert input_tokens >= total_detailed_tokens
         if "cache_creation_input" in self.supported_usage_metadata_details["invoke"]:
             msg = self.invoke_with_cache_creation_input()
-            assert (usage_metadata := msg.usage_metadata) is not None
-            assert (
-                input_token_details := usage_metadata.get("input_token_details")
-            ) is not None
-            assert isinstance(input_token_details.get("cache_creation"), int)
+            usage_metadata = msg.usage_metadata
+            assert usage_metadata is not None
+            input_token_details = usage_metadata.get("input_token_details")
+            assert input_token_details is not None
+            cache_creation_tokens = input_token_details.get("cache_creation")
+            assert isinstance(cache_creation_tokens, int)
+            assert cache_creation_tokens >= 0
             # Asserts that total input tokens are at least the sum of the token counts
-            assert usage_metadata.get("input_tokens", 0) >= sum(
-                v for v in input_token_details.values() if isinstance(v, int)
+            total_detailed_tokens = sum(
+                v for v in input_token_details.values() if isinstance(v, int) and v >= 0
             )
+            input_tokens = usage_metadata.get("input_tokens", 0)
+            assert isinstance(input_tokens, int)
+            assert input_tokens >= total_detailed_tokens
 
     def test_usage_metadata_streaming(self, model: BaseChatModel) -> None:
         """Test usage metadata in streaming mode.