Harrison/gpt cache (#2744)

Co-authored-by: SimFG <bang.fu@zilliz.com>

tests/integration_tests/cache/__init__.py

@@ -0,0 +1 @@
+"""All integration tests for Cache objects."""

tests/integration_tests/cache/test_gptcache.py

@@ -0,0 +1,61 @@
+import os
+
+import pytest
+
+import langchain
+from langchain.cache import GPTCache
+from langchain.schema import Generation, LLMResult
+from tests.unit_tests.llms.fake_llm import FakeLLM
+
+try:
+    import gptcache  # noqa: F401
+
+    gptcache_installed = True
+except ImportError:
+    gptcache_installed = False
+
+
+@pytest.mark.skipif(not gptcache_installed, reason="gptcache not installed")
+def test_gptcache_map_caching() -> None:
+    """Test gptcache caching behavior."""
+
+    from gptcache import Cache
+    from gptcache.manager.factory import get_data_manager
+    from gptcache.processor.pre import get_prompt
+
+    i = 0
+    file_prefix = "data_map"
+
+    def init_gptcache_map(cache_obj: Cache) -> None:
+        nonlocal i
+        cache_path = f"{file_prefix}_{i}.txt"
+        if os.path.isfile(cache_path):
+            os.remove(cache_path)
+        cache_obj.init(
+            pre_embedding_func=get_prompt,
+            data_manager=get_data_manager(data_path=cache_path),
+        )
+        i += 1
+
+    langchain.llm_cache = GPTCache(init_gptcache_map)
+
+    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