langchain[patch],community[minor]: Move some unit tests from langchain to community, use core for fake models (#21190)

libs/community/scripts/lint_imports.sh

@@ -6,7 +6,6 @@ set -eu
 errors=0
 
 # make sure not importing from langchain or langchain_experimental
-git --no-pager grep '^from langchain\.' . && errors=$((errors+1))
 git --no-pager grep '^from langchain_experimental\.' . && errors=$((errors+1))
 
 # Decide on an exit status based on the errors

libs/community/tests/unit_tests/retrievers/document_compressors/test_cohere_rerank.py

@@ -3,8 +3,10 @@ import os
 import pytest
 from pytest_mock import MockerFixture
 
-from langchain.retrievers.document_compressors import CohereRerank
-from langchain.schema import Document
+pytest.importorskip("langchain")
+
+from langchain.retrievers.document_compressors import CohereRerank  # noqa: E402
+from langchain.schema import Document  # noqa: E402
 
 os.environ["COHERE_API_KEY"] = "foo"
 

libs/community/tests/unit_tests/retrievers/document_compressors/test_cross_encoder_reranker.py

@@ -1,10 +1,14 @@
 """Integration test for CrossEncoderReranker."""
 from typing import List
 
-from langchain_community.cross_encoders import FakeCrossEncoder
+import pytest
 from langchain_core.documents import Document
 
-from langchain.retrievers.document_compressors import CrossEncoderReranker
+from langchain_community.cross_encoders import FakeCrossEncoder
+
+pytest.importorskip("langchain")
+
+from langchain.retrievers.document_compressors import CrossEncoderReranker  # noqa: E402
 
 
 def test_rerank() -> None:

libs/langchain/langchain/llms/__init__.py

@@ -177,7 +177,7 @@ def _import_edenai() -> Any:
 
 
 def _import_fake() -> Any:
-    from langchain_community.llms.fake import FakeListLLM
+    from langchain_core.language_models import FakeListLLM
 
     return FakeListLLM
 

libs/langchain/langchain/llms/fake.py

@@ -3,8 +3,8 @@ from typing import TYPE_CHECKING, Any
 from langchain._api import create_importer
 
 if TYPE_CHECKING:
-    from langchain_community.llms import FakeListLLM
     from langchain_community.llms.fake import FakeStreamingListLLM
+    from langchain_core.language_models import FakeListLLM
 
 # Create a way to dynamically look up deprecated imports.
 # Used to consolidate logic for raising deprecation warnings and

libs/langchain/tests/unit_tests/agents/test_agent_iterator.py

@@ -1,7 +1,7 @@
 from uuid import UUID
 
 import pytest
-from langchain_community.llms import FakeListLLM
+from langchain_core.language_models import FakeListLLM
 from langchain_core.tools import Tool
 
 from langchain.agents import (

libs/langchain/tests/unit_tests/agents/test_react.py

@@ -2,9 +2,9 @@
 
 from typing import Union
 
-from langchain_community.llms.fake import FakeListLLM
 from langchain_core.agents import AgentAction
 from langchain_core.documents import Document
+from langchain_core.language_models import FakeListLLM
 from langchain_core.prompts.prompt import PromptTemplate
 from langchain_core.tools import Tool
 

libs/langchain/tests/unit_tests/agents/test_serialization.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 from tempfile import TemporaryDirectory
 
-from langchain_community.llms.fake import FakeListLLM
+from langchain_core.language_models import FakeListLLM
 from langchain_core.tools import Tool
 
 from langchain.agents.agent_types import AgentType

libs/langchain/tests/unit_tests/chains/test_conversation_retrieval.py

@@ -1,6 +1,6 @@
 """Test conversation chain and memory."""
-from langchain_community.llms.fake import FakeListLLM
 from langchain_core.documents import Document
+from langchain_core.language_models import FakeListLLM
 
 from langchain.chains.conversational_retrieval.base import (
     ConversationalRetrievalChain,

libs/langchain/tests/unit_tests/chains/test_history_aware_retriever.py

@@ -1,5 +1,5 @@
-from langchain_community.llms.fake import FakeListLLM
 from langchain_core.documents import Document
+from langchain_core.language_models import FakeListLLM
 from langchain_core.prompts import PromptTemplate
 
 from langchain.chains import create_history_aware_retriever

libs/langchain/tests/unit_tests/chains/test_retrieval.py

@@ -1,6 +1,6 @@
 """Test conversation chain and memory."""
-from langchain_community.llms.fake import FakeListLLM
 from langchain_core.documents import Document
+from langchain_core.language_models import FakeListLLM
 from langchain_core.prompts.prompt import PromptTemplate
 
 from langchain.chains import create_retrieval_chain

libs/langchain/tests/unit_tests/evaluation/test_loading.py

@@ -2,7 +2,7 @@
 from typing import List
 
 import pytest
-from langchain_community.embeddings.fake import FakeEmbeddings
+from langchain_core.embeddings import FakeEmbeddings
 
 from langchain.evaluation.loading import EvaluatorType, load_evaluators
 from langchain.evaluation.schema import PairwiseStringEvaluator, StringEvaluator

libs/langchain/tests/unit_tests/test_cache.py

@@ -4,9 +4,8 @@ from typing import Dict, Generator, List, Union
 
 import pytest
 from _pytest.fixtures import FixtureRequest
-from langchain_community.chat_models import FakeListChatModel
-from langchain_community.llms import FakeListLLM
 from langchain_core.caches import InMemoryCache
+from langchain_core.language_models import FakeListChatModel, FakeListLLM
 from langchain_core.language_models.chat_models import BaseChatModel
 from langchain_core.language_models.llms import BaseLLM
 from langchain_core.load import dumps