mongodb[minor]: MongoDB Partner Package -- Porting MongoDBAtlasVectorSearch (#17652)

This PR migrates the existing MongoDBAtlasVectorSearch abstraction from
the `langchain_community` section to the partners package section of the
codebase.
- [x] Run the partner package script as advised in the partner-packages
documentation.
- [x] Add Unit Tests
- [x] Migrate Integration Tests
- [x] Refactor `MongoDBAtlasVectorStore` (autogenerated) to
`MongoDBAtlasVectorSearch`
- [x] ~Remove~ deprecate the old `langchain_community` VectorStore
references.

## Additional Callouts
- Implemented the `delete` method
- Included any missing async function implementations
  - `amax_marginal_relevance_search_by_vector`
  - `adelete` 
- Added new Unit Tests that test for functionality of
`MongoDBVectorSearch` methods
- Removed [`del
res[self._embedding_key]`](e0c81e1cb0/libs/community/langchain_community/vectorstores/mongodb_atlas.py (L218))
in `_similarity_search_with_score` function as it would make the
`maximal_marginal_relevance` function fail otherwise. The `Document`
needs to store the embedding key in metadata to work.

Checklist:

- [x] PR title: Please title your PR "package: description", where
"package" is whichever of langchain, community, core, experimental, etc.
is being modified. Use "docs: ..." for purely docs changes, "templates:
..." for template changes, "infra: ..." for CI changes.
  - Example: "community: add foobar LLM"
- [x] PR message
- [x] Pass lint and test: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified to check that you're
passing lint and testing. See contribution guidelines for more
information on how to write/run tests, lint, etc:
https://python.langchain.com/docs/contributing/
- [x] Add tests and docs: If you're adding a new integration, please
include
1. Existing tests supplied in docs/docs do not change. Updated
docstrings for new functions like `delete`
2. an example notebook showing its use. It lives in
`docs/docs/integrations` directory. (This already exists)

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, hwchase17.

---------

Co-authored-by: Steven Silvester <steven.silvester@ieee.org>
Co-authored-by: Erick Friis <erick@langchain.dev>

libs/partners/mongodb/tests/integration_tests/test_compile.py

@@ -0,0 +1,7 @@
+import pytest
+
+
+@pytest.mark.compile
+def test_placeholder() -> None:
+    """Used for compiling integration tests without running any real tests."""
+    pass

libs/partners/mongodb/tests/integration_tests/test_vectorstores.py

@@ -0,0 +1,170 @@
+"""Test MongoDB Atlas Vector Search functionality."""
+
+from __future__ import annotations
+
+import os
+from time import sleep
+from typing import Any, Dict, List
+
+import pytest
+from langchain_core.documents import Document
+from langchain_core.embeddings import Embeddings
+from pymongo import MongoClient
+from pymongo.collection import Collection
+
+from langchain_mongodb import MongoDBAtlasVectorSearch
+from tests.utils import ConsistentFakeEmbeddings
+
+INDEX_NAME = "langchain-test-index"
+NAMESPACE = "langchain_test_db.langchain_test_collection"
+CONNECTION_STRING = os.environ.get("MONGODB_ATLAS_URI")
+DB_NAME, COLLECTION_NAME = NAMESPACE.split(".")
+DIMENSIONS = 1536
+TIMEOUT = 10.0
+INTERVAL = 0.5
+
+
+class PatchedMongoDBAtlasVectorSearch(MongoDBAtlasVectorSearch):
+    def _insert_texts(self, texts: List[str], metadatas: List[Dict[str, Any]]) -> List:
+        """Patched insert_texts that waits for data to be indexed before returning"""
+        ids = super()._insert_texts(texts, metadatas)
+        timeout = TIMEOUT
+        while len(ids) != self.similarity_search("sandwich") and timeout >= 0:
+            sleep(INTERVAL)
+            timeout -= INTERVAL
+        return ids
+
+
+def get_collection() -> Collection:
+    test_client: MongoClient = MongoClient(CONNECTION_STRING)
+    return test_client[DB_NAME][COLLECTION_NAME]
+
+
+@pytest.fixture()
+def collection() -> Collection:
+    return get_collection()
+
+
+class TestMongoDBAtlasVectorSearch:
+    @classmethod
+    def setup_class(cls) -> None:
+        # insure the test collection is empty
+        collection = get_collection()
+        assert collection.count_documents({}) == 0  # type: ignore[index]  # noqa: E501
+
+    @classmethod
+    def teardown_class(cls) -> None:
+        collection = get_collection()
+        # delete all the documents in the collection
+        collection.delete_many({})  # type: ignore[index]
+
+    @pytest.fixture(autouse=True)
+    def setup(self) -> None:
+        collection = get_collection()
+        # delete all the documents in the collection
+        collection.delete_many({})  # type: ignore[index]
+
+    @pytest.fixture
+    def embedding_openai(self) -> Embeddings:
+        return ConsistentFakeEmbeddings(DIMENSIONS)
+
+    def test_from_documents(
+        self, embedding_openai: Embeddings, collection: Any
+    ) -> None:
+        """Test end to end construction and search."""
+        documents = [
+            Document(page_content="Dogs are tough.", metadata={"a": 1}),
+            Document(page_content="Cats have fluff.", metadata={"b": 1}),
+            Document(page_content="What is a sandwich?", metadata={"c": 1}),
+            Document(page_content="That fence is purple.", metadata={"d": 1, "e": 2}),
+        ]
+        vectorstore = PatchedMongoDBAtlasVectorSearch.from_documents(
+            documents,
+            embedding_openai,
+            collection=collection,
+            index_name=INDEX_NAME,
+        )
+        # sleep(5)  # waits for mongot to update Lucene's index
+        output = vectorstore.similarity_search("Sandwich", k=1)
+        assert len(output) == 1
+        # Check for the presence of the metadata key
+        assert any([key.page_content == output[0].page_content for key in documents])
+
+    def test_from_texts(self, embedding_openai: Embeddings, collection: Any) -> None:
+        texts = [
+            "Dogs are tough.",
+            "Cats have fluff.",
+            "What is a sandwich?",
+            "That fence is purple.",
+        ]
+        vectorstore = PatchedMongoDBAtlasVectorSearch.from_texts(
+            texts,
+            embedding_openai,
+            collection=collection,
+            index_name=INDEX_NAME,
+        )
+        # sleep(5)  # waits for mongot to update Lucene's index
+        output = vectorstore.similarity_search("Sandwich", k=1)
+        assert len(output) == 1
+
+    def test_from_texts_with_metadatas(
+        self, embedding_openai: Embeddings, collection: Any
+    ) -> None:
+        texts = [
+            "Dogs are tough.",
+            "Cats have fluff.",
+            "What is a sandwich?",
+            "The fence is purple.",
+        ]
+        metadatas = [{"a": 1}, {"b": 1}, {"c": 1}, {"d": 1, "e": 2}]
+        metakeys = ["a", "b", "c", "d", "e"]
+        vectorstore = PatchedMongoDBAtlasVectorSearch.from_texts(
+            texts,
+            embedding_openai,
+            metadatas=metadatas,
+            collection=collection,
+            index_name=INDEX_NAME,
+        )
+        # sleep(5)  # waits for mongot to update Lucene's index
+        output = vectorstore.similarity_search("Sandwich", k=1)
+        assert len(output) == 1
+        # Check for the presence of the metadata key
+        assert any([key in output[0].metadata for key in metakeys])
+
+    def test_from_texts_with_metadatas_and_pre_filter(
+        self, embedding_openai: Embeddings, collection: Any
+    ) -> None:
+        texts = [
+            "Dogs are tough.",
+            "Cats have fluff.",
+            "What is a sandwich?",
+            "The fence is purple.",
+        ]
+        metadatas = [{"a": 1}, {"b": 1}, {"c": 1}, {"d": 1, "e": 2}]
+        vectorstore = PatchedMongoDBAtlasVectorSearch.from_texts(
+            texts,
+            embedding_openai,
+            metadatas=metadatas,
+            collection=collection,
+            index_name=INDEX_NAME,
+        )
+        # sleep(5)  # waits for mongot to update Lucene's index
+        output = vectorstore.similarity_search(
+            "Sandwich", k=1, pre_filter={"c": {"$lte": 0}}
+        )
+        assert output == []
+
+    def test_mmr(self, embedding_openai: Embeddings, collection: Any) -> None:
+        texts = ["foo", "foo", "fou", "foy"]
+        vectorstore = PatchedMongoDBAtlasVectorSearch.from_texts(
+            texts,
+            embedding_openai,
+            collection=collection,
+            index_name=INDEX_NAME,
+        )
+        # sleep(5)  # waits for mongot to update Lucene's index
+        query = "foo"
+        output = vectorstore.max_marginal_relevance_search(query, k=10, lambda_mult=0.1)
+        assert len(output) == len(texts)
+        assert output[0].page_content == "foo"
+        assert output[1].page_content != "foo"