add test

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

@@ -8,6 +8,7 @@
 from langchain_core.messages import (
     AIMessage,
     AIMessageChunk,
+    BaseMessage,
     BaseMessageChunk,
     HumanMessage,
     SystemMessage,
@@ -28,7 +29,13 @@ def magic_function(input: int) -> int:
     return input + 2
 
 
-def _validate_tool_call_message(message: AIMessage) -> None:
+@tool
+def magic_function_no_args() -> int:
+    """Calculates a magic function."""
+    return 5
+
+
+def _validate_tool_call_message(message: BaseMessage) -> None:
     assert isinstance(message, AIMessage)
     assert len(message.tool_calls) == 1
     tool_call = message.tool_calls[0]
@@ -37,6 +44,15 @@ def _validate_tool_call_message(message: AIMessage) -> None:
     assert tool_call["id"] is not None
 
 
+def _validate_tool_call_message_no_args(message: BaseMessage) -> None:
+    assert isinstance(message, AIMessage)
+    assert len(message.tool_calls) == 1
+    tool_call = message.tool_calls[0]
+    assert tool_call["name"] == "magic_function_no_args"
+    assert tool_call["args"] == {}
+    assert tool_call["id"] is not None
+
+
 class ChatModelIntegrationTests(ChatModelTests):
     def test_invoke(self, model: BaseChatModel) -> None:
         result = model.invoke("Hello")
@@ -131,7 +147,6 @@ def test_tool_calling(self, model: BaseChatModel) -> None:
         # Test invoke
         query = "What is the value of magic_function(3)? Use the tool."
         result = model_with_tools.invoke(query)
-        assert isinstance(result, AIMessage)
         _validate_tool_call_message(result)
 
         # Test stream
@@ -141,6 +156,18 @@ def test_tool_calling(self, model: BaseChatModel) -> None:
         assert isinstance(full, AIMessage)
         _validate_tool_call_message(full)
 
+        # Test tool with no arguments
+        model_with_tools = model.bind_tools([magic_function_no_args])
+        query = "What is the value of magic_function()? Use the tool."
+        result = model_with_tools.invoke(query)
+        _validate_tool_call_message_no_args(result)
+
+        full = None
+        for chunk in model_with_tools.stream(query):
+            full = chunk if full is None else full + chunk  # type: ignore
+        assert isinstance(full, AIMessage)
+        _validate_tool_call_message_no_args(full)
+
     def test_structured_output(self, model: BaseChatModel) -> None:
         if not self.has_tool_calling:
             pytest.skip("Test requires tool calling.")