tests: init retriever standard tests (#28459)

libs/standard-tests/langchain_tests/integration_tests/__init__.py

@@ -20,6 +20,7 @@ from .base_store import BaseStoreAsyncTests, BaseStoreSyncTests
 from .cache import AsyncCacheTestSuite, SyncCacheTestSuite
 from .chat_models import ChatModelIntegrationTests
 from .embeddings import EmbeddingsIntegrationTests
+from .retrievers import RetrieversIntegrationTests
 from .tools import ToolsIntegrationTests
 from .vectorstores import AsyncReadWriteTestSuite, ReadWriteTestSuite
 
@@ -33,4 +34,5 @@ __all__ = [
     "SyncCacheTestSuite",
     "AsyncReadWriteTestSuite",
     "ReadWriteTestSuite",
+    "RetrieversIntegrationTests",
 ]

libs/standard-tests/langchain_tests/integration_tests/retrievers.py

@@ -0,0 +1,78 @@
+from abc import abstractmethod
+from typing import Type
+
+import pytest
+from langchain_core.documents import Document
+from langchain_core.retrievers import BaseRetriever
+
+from langchain_tests.base import BaseStandardTests
+
+
+class RetrieversIntegrationTests(BaseStandardTests):
+    @property
+    @abstractmethod
+    def retriever_constructor(self) -> Type[BaseRetriever]: ...
+
+    @property
+    def retriever_constructor_params(self) -> dict:
+        return {}
+
+    @property
+    @abstractmethod
+    def retriever_query_example(self) -> str:
+        """
+        Returns a dictionary representing the "args" of an example retriever call.
+        """
+        ...
+
+    @pytest.fixture
+    def retriever(self) -> BaseRetriever:
+        return self.retriever_constructor(**self.retriever_constructor_params)
+
+    def test_k_constructor_param(self) -> None:
+        """
+        Test that the retriever constructor accepts a k parameter.
+        """
+        params = {
+            k: v for k, v in self.retriever_constructor_params.items() if k != "k"
+        }
+        params_3 = {**params, "k": 3}
+        retriever_3 = self.retriever_constructor(**params_3)
+        result_3 = retriever_3.invoke(self.retriever_query_example)
+        assert len(result_3) == 3
+        assert all(isinstance(doc, Document) for doc in result_3)
+
+        params_1 = {**params, "k": 1}
+        retriever_1 = self.retriever_constructor(**params_1)
+        result_1 = retriever_1.invoke(self.retriever_query_example)
+        assert len(result_1) == 1
+        assert all(isinstance(doc, Document) for doc in result_1)
+
+    def test_invoke_with_k_kwarg(self, retriever: BaseRetriever) -> None:
+        result_1 = retriever.invoke(self.retriever_query_example, k=1)
+        assert len(result_1) == 1
+        assert all(isinstance(doc, Document) for doc in result_1)
+
+        result_3 = retriever.invoke(self.retriever_query_example, k=3)
+        assert len(result_3) == 3
+        assert all(isinstance(doc, Document) for doc in result_3)
+
+    def test_invoke_returns_documents(self, retriever: BaseRetriever) -> None:
+        """
+        If invoked with the example params, the retriever should return a list of
+        Documents.
+        """
+        result = retriever.invoke(self.retriever_query_example)
+
+        assert isinstance(result, list)
+        assert all(isinstance(doc, Document) for doc in result)
+
+    async def test_ainvoke_returns_documents(self, retriever: BaseRetriever) -> None:
+        """
+        If ainvoked with the example params, the retriever should return a list of
+        Documents.
+        """
+        result = await retriever.ainvoke(self.retriever_query_example)
+
+        assert isinstance(result, list)
+        assert all(isinstance(doc, Document) for doc in result)

libs/standard-tests/tests/unit_tests/test_basic_retriever.py

@@ -0,0 +1,32 @@
+from typing import Any, Type
+
+from langchain_core.callbacks import CallbackManagerForRetrieverRun
+from langchain_core.documents import Document
+from langchain_core.retrievers import BaseRetriever
+
+from langchain_tests.integration_tests import RetrieversIntegrationTests
+
+
+class ParrotRetriever(BaseRetriever):
+    parrot_name: str
+    k: int = 3
+
+    def _get_relevant_documents(
+        self, query: str, *, run_manager: CallbackManagerForRetrieverRun, **kwargs: Any
+    ) -> list[Document]:
+        k = kwargs.get("k", self.k)
+        return [Document(page_content=f"{self.parrot_name} says: {query}")] * k
+
+
+class TestParrotRetrieverIntegration(RetrieversIntegrationTests):
+    @property
+    def retriever_constructor(self) -> Type[ParrotRetriever]:
+        return ParrotRetriever
+
+    @property
+    def retriever_constructor_params(self) -> dict:
+        return {"parrot_name": "Polly"}
+
+    @property
+    def retriever_query_example(self) -> str:
+        return "parrot"