Test to verify that model.invoke(simple_message) works.
This should pass for all integrations.
If this test fails, you should make sure your _generate method
does not raise any exceptions, and that it returns a valid
langchain_core.outputs.chat_result.ChatResult like so:
return ChatResult(
generations=[ChatGeneration(message=AIMessage(content="Output text"))]
)test_invoke(
self,
model: BaseChatModel,
) -> None