multiple: langchain 0.2 in master (#21191)

0.2rc 

migrations

- [x] Move memory
- [x] Move remaining retrievers
- [x] graph_qa chains
- [x] some dependency from evaluation code potentially on math utils
- [x] Move openapi chain from `langchain.chains.api.openapi` to
`langchain_community.chains.openapi`
- [x] Migrate `langchain.chains.ernie_functions` to
`langchain_community.chains.ernie_functions`
- [x] migrate `langchain/chains/llm_requests.py` to
`langchain_community.chains.llm_requests`
- [x] Moving `langchain_community.cross_enoders.base:BaseCrossEncoder`
->
`langchain_community.retrievers.document_compressors.cross_encoder:BaseCrossEncoder`
(namespace not ideal, but it needs to be moved to `langchain` to avoid
circular deps)
- [x] unit tests langchain -- add pytest.mark.community to some unit
tests that will stay in langchain
- [x] unit tests community -- move unit tests that depend on community
to community
- [x] mv integration tests that depend on community to community
- [x] mypy checks

Other todo

- [x] Make deprecation warnings not noisy (need to use warn deprecated
and check that things are implemented properly)
- [x] Update deprecation messages with timeline for code removal (likely
we actually won't be removing things until 0.4 release) -- will give
people more time to transition their code.
- [ ] Add information to deprecation warning to show users how to
migrate their code base using langchain-cli
- [ ] Remove any unnecessary requirements in langchain (e.g., is
SQLALchemy required?)

---------

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/tests/unit_tests/chains/test_api.py

@@ -0,0 +1,105 @@
+"""Test LLM Math functionality."""
+
+import json
+from typing import Any
+
+import pytest
+from langchain.chains.api.base import APIChain
+from langchain.chains.api.prompt import API_RESPONSE_PROMPT, API_URL_PROMPT
+from langchain.chains.llm import LLMChain
+
+from langchain_community.utilities.requests import TextRequestsWrapper
+from tests.unit_tests.llms.fake_llm import FakeLLM
+
+
+class FakeRequestsChain(TextRequestsWrapper):
+    """Fake requests chain just for testing purposes."""
+
+    output: str
+
+    def get(self, url: str, **kwargs: Any) -> str:
+        """Just return the specified output."""
+        return self.output
+
+
+def get_test_api_data() -> dict:
+    """Fake api data to use for testing."""
+    api_docs = """
+    This API endpoint will search the notes for a user.
+
+    Endpoint: https://thisapidoesntexist.com
+    GET /api/notes
+
+    Query parameters:
+    q | string | The search term for notes
+    """
+    return {
+        "api_docs": api_docs,
+        "question": "Search for notes containing langchain",
+        "api_url": "https://thisapidoesntexist.com/api/notes?q=langchain",
+        "api_response": json.dumps(
+            {
+                "success": True,
+                "results": [{"id": 1, "content": "Langchain is awesome!"}],
+            }
+        ),
+        "api_summary": "There is 1 note about langchain.",
+    }
+
+
+def get_api_chain(**kwargs: Any) -> APIChain:
+    """Fake LLM API chain for testing."""
+    data = get_test_api_data()
+    test_api_docs = data["api_docs"]
+    test_question = data["question"]
+    test_url = data["api_url"]
+    test_api_response = data["api_response"]
+    test_api_summary = data["api_summary"]
+
+    api_url_query_prompt = API_URL_PROMPT.format(
+        api_docs=test_api_docs, question=test_question
+    )
+    api_response_prompt = API_RESPONSE_PROMPT.format(
+        api_docs=test_api_docs,
+        question=test_question,
+        api_url=test_url,
+        api_response=test_api_response,
+    )
+    queries = {api_url_query_prompt: test_url, api_response_prompt: test_api_summary}
+    fake_llm = FakeLLM(queries=queries)
+    api_request_chain = LLMChain(llm=fake_llm, prompt=API_URL_PROMPT)
+    api_answer_chain = LLMChain(llm=fake_llm, prompt=API_RESPONSE_PROMPT)
+    requests_wrapper = FakeRequestsChain(output=test_api_response)
+    return APIChain(
+        api_request_chain=api_request_chain,
+        api_answer_chain=api_answer_chain,
+        requests_wrapper=requests_wrapper,
+        api_docs=test_api_docs,
+        **kwargs,
+    )
+
+
+def test_api_question() -> None:
+    """Test simple question that needs API access."""
+    with pytest.raises(ValueError):
+        get_api_chain()
+    with pytest.raises(ValueError):
+        get_api_chain(limit_to_domains=tuple())
+
+    # All domains allowed (not advised)
+    api_chain = get_api_chain(limit_to_domains=None)
+    data = get_test_api_data()
+    assert api_chain.run(data["question"]) == data["api_summary"]
+
+    # Use a domain that's allowed
+    api_chain = get_api_chain(
+        limit_to_domains=["https://thisapidoesntexist.com/api/notes?q=langchain"]
+    )
+    # Attempts to make a request against a domain that's not allowed
+    assert api_chain.run(data["question"]) == data["api_summary"]
+
+    # Use domains that are not valid
+    api_chain = get_api_chain(limit_to_domains=["h", "*"])
+    with pytest.raises(ValueError):
+        # Attempts to make a request against a domain that's not allowed
+        assert api_chain.run(data["question"]) == data["api_summary"]