langchain/tests/unit_tests/llms/test_base.py

"""Test base LLM functionality."""
from sqlalchemy import Column, Integer, Sequence, String, create_engine

try:
    from sqlalchemy.orm import declarative_base
except ImportError:
    from sqlalchemy.ext.declarative import declarative_base

import langchain
from langchain.cache import InMemoryCache, SQLAlchemyCache
from langchain.schema import Generation, LLMResult
from tests.unit_tests.llms.fake_llm import FakeLLM


def test_caching() -> None:
    """Test caching behavior."""
    langchain.llm_cache = InMemoryCache()
    llm = FakeLLM()
    params = llm.dict()
    params["stop"] = None
    llm_string = str(sorted([(k, v) for k, v in params.items()]))
    langchain.llm_cache.update("foo", llm_string, [Generation(text="fizz")])
    output = llm.generate(["foo", "bar", "foo"])
    expected_cache_output = [Generation(text="foo")]
    cache_output = langchain.llm_cache.lookup("bar", llm_string)
    assert cache_output == expected_cache_output
    langchain.llm_cache = None
    expected_generations = [
        [Generation(text="fizz")],
        [Generation(text="foo")],
        [Generation(text="fizz")],
    ]
    expected_output = LLMResult(
        generations=expected_generations,
        llm_output=None,
    )
    assert output == expected_output


def test_custom_caching() -> None:
    """Test custom_caching behavior."""
    Base = declarative_base()

    class FulltextLLMCache(Base):  # type: ignore
        """Postgres table for fulltext-indexed LLM Cache."""

        __tablename__ = "llm_cache_fulltext"
        id = Column(Integer, Sequence("cache_id"), primary_key=True)
        prompt = Column(String, nullable=False)
        llm = Column(String, nullable=False)
        idx = Column(Integer)
        response = Column(String)

    engine = create_engine("sqlite://")
    langchain.llm_cache = SQLAlchemyCache(engine, FulltextLLMCache)
    llm = FakeLLM()
    params = llm.dict()
    params["stop"] = None
    llm_string = str(sorted([(k, v) for k, v in params.items()]))
    langchain.llm_cache.update("foo", llm_string, [Generation(text="fizz")])
    output = llm.generate(["foo", "bar", "foo"])
    expected_cache_output = [Generation(text="foo")]
    cache_output = langchain.llm_cache.lookup("bar", llm_string)
    assert cache_output == expected_cache_output
    langchain.llm_cache = None
    expected_generations = [
        [Generation(text="fizz")],
        [Generation(text="foo")],
        [Generation(text="fizz")],
    ]
    expected_output = LLMResult(
        generations=expected_generations,
        llm_output=None,
    )
    assert output == expected_output