langchain/libs/partners/mongodb/tests/unit_tests/test_chat_message_histories.py

import json

from langchain.memory import ConversationBufferMemory
from langchain_core.messages import message_to_dict

from langchain_mongodb.chat_message_histories import MongoDBChatMessageHistory
from tests.utils import MockCollection


class PatchedMongoDBChatMessageHistory(MongoDBChatMessageHistory):
    def __init__(self) -> None:
        self.session_id = "test-session"
        self.database_name = "test-database"
        self.collection_name = "test-collection"
        self.collection = MockCollection()


def test_memory_with_message_store() -> None:
    """Test the memory with a message store."""
    # setup MongoDB as a message store
    message_history = PatchedMongoDBChatMessageHistory()
    memory = ConversationBufferMemory(
        memory_key="baz", chat_memory=message_history, return_messages=True
    )

    # add some messages
    memory.chat_memory.add_ai_message("This is me, the AI")
    memory.chat_memory.add_user_message("This is me, the human")

    # get the message history from the memory store and turn it into a json
    messages = memory.chat_memory.messages
    messages_json = json.dumps([message_to_dict(msg) for msg in messages])

    assert "This is me, the AI" in messages_json
    assert "This is me, the human" in messages_json

    # remove the record from MongoDB, so the next test run won't pick it up
    memory.chat_memory.clear()

    assert memory.chat_memory.messages == []