langchain - 💡(How to fix) Fix test_stream_error_callback expects [] instead of [[]] for empty stream error result [1 comments, 2 participants]

import pytest
from langchain_core.language_models import FakeListChatModel
from langchain_core.language_models.fake_chat_models import FakeListChatModelError
from langchain_core.outputs.llm_result import LLMResult
from tests.unit_tests.fake.callbacks import BaseFakeCallbackHandler, FakeAsyncCallbackHandler, FakeCallbackHandler


async def test_stream_error_callback() -> None:
    message = "test"

    def eval_response(callback: BaseFakeCallbackHandler, i: int) -> None:
        assert callback.errors == 1
        assert len(callback.errors_args) == 1
        llm_result: LLMResult = callback.errors_args[0]["kwargs"]["response"]
        if i == 0:
            assert llm_result.generations == []
        else:
            assert llm_result.generations[0][0].text == message[:i]

    for i in range(len(message)):
        llm = FakeListChatModel(
            responses=[message],
            error_on_chunk_number=i,
        )
        cb_async = FakeAsyncCallbackHandler()
        llm_astream = llm.astream("Dummy message", config={"callbacks": [cb_async]})
        for _ in range(i):
            await anext(llm_astream)
        with pytest.raises(FakeListChatModelError):
            await anext(llm_astream)
        eval_response(cb_async, i)

        cb_sync = FakeCallbackHandler()
        llm_stream = llm.stream("Dumy message", config={"callbacks": [cb_sync]})
        for _ in range(i):
            next(llm_stream)
        with pytest.raises(FakeListChatModelError):
            next(llm_stream)
        eval_response(cb_sync, i)

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E           assert [[]] == []
E             
E             Left contains one more item: []