feat: implement keyword and hybrid search for Weaviate provider

llama_stack/providers/remote/vector_io/weaviate/weaviate.py

@@ -10,7 +10,7 @@ import weaviate
 import weaviate.classes as wvc
 from numpy.typing import NDArray
 from weaviate.classes.init import Auth
-from weaviate.classes.query import Filter
+from weaviate.classes.query import Filter, HybridFusion
 
 from llama_stack.apis.common.content_types import InterleavedContent
 from llama_stack.apis.common.errors import VectorStoreNotFoundError
@@ -26,6 +26,7 @@ from llama_stack.providers.utils.memory.openai_vector_store_mixin import (
     OpenAIVectorStoreMixin,
 )
 from llama_stack.providers.utils.memory.vector_store import (
+    RERANKER_TYPE_RRF,
     ChunkForDeletion,
     EmbeddingIndex,
     VectorDBWithIndex,
@@ -88,6 +89,9 @@ class WeaviateIndex(EmbeddingIndex):
         collection.data.delete_many(where=Filter.by_property("chunk_id").contains_any(chunk_ids))
 
     async def query_vector(self, embedding: NDArray, k: int, score_threshold: float) -> QueryChunksResponse:
+        log.info(
+            f"WEAVIATE VECTOR SEARCH CALLED: embedding_shape={embedding.shape}, k={k}, threshold={score_threshold}"
+        )
         sanitized_collection_name = sanitize_collection_name(self.collection_name, weaviate_format=True)
         collection = self.client.collections.get(sanitized_collection_name)
 
@@ -115,6 +119,7 @@ class WeaviateIndex(EmbeddingIndex):
             chunks.append(chunk)
             scores.append(score)
 
+        log.info(f"WEAVIATE VECTOR SEARCH RESULTS: Found {len(chunks)} chunks with scores {scores}")
         return QueryChunksResponse(chunks=chunks, scores=scores)
 
     async def delete(self, chunk_ids: list[str] | None = None) -> None:
@@ -136,7 +141,46 @@ class WeaviateIndex(EmbeddingIndex):
         k: int,
         score_threshold: float,
     ) -> QueryChunksResponse:
-        raise NotImplementedError("Keyword search is not supported in Weaviate")
+        """
+        Performs BM25-based keyword search using Weaviate's built-in full-text search.
+        Args:
+            query_string: The text query for keyword search
+            k: Limit of number of results to return
+            score_threshold: Minimum similarity score threshold
+        Returns:
+            QueryChunksResponse with combined results
+        """
+        log.info(f"WEAVIATE KEYWORD SEARCH CALLED: query='{query_string}', k={k}, threshold={score_threshold}")
+        sanitized_collection_name = sanitize_collection_name(self.collection_name, weaviate_format=True)
+        collection = self.client.collections.get(sanitized_collection_name)
+
+        # Perform BM25 keyword search on chunk_content field
+        results = collection.query.bm25(
+            query=query_string,
+            limit=k,
+            return_metadata=wvc.query.MetadataQuery(score=True),
+        )
+
+        chunks = []
+        scores = []
+        for doc in results.objects:
+            chunk_json = doc.properties["chunk_content"]
+            try:
+                chunk_dict = json.loads(chunk_json)
+                chunk = Chunk(**chunk_dict)
+            except Exception:
+                log.exception(f"Failed to parse document: {chunk_json}")
+                continue
+
+            score = doc.metadata.score if doc.metadata.score is not None else 0.0
+            if score < score_threshold:
+                continue
+
+            chunks.append(chunk)
+            scores.append(score)
+
+        log.info(f"WEAVIATE KEYWORD SEARCH RESULTS: Found {len(chunks)} chunks with scores {scores}.")
+        return QueryChunksResponse(chunks=chunks, scores=scores)
 
     async def query_hybrid(
         self,
@@ -147,7 +191,62 @@ class WeaviateIndex(EmbeddingIndex):
         reranker_type: str,
         reranker_params: dict[str, Any] | None = None,
     ) -> QueryChunksResponse:
-        raise NotImplementedError("Hybrid search is not supported in Weaviate")
+        """
+        Hybrid search combining vector similarity and keyword search using Weaviate's native hybrid search.
+        Args:
+            embedding: The query embedding vector
+            query_string: The text query for keyword search
+            k: Limit of number of results to return
+            score_threshold: Minimum similarity score threshold
+            reranker_type: Type of reranker to use ("rrf" or "normalized")
+            reranker_params: Parameters for the reranker
+        Returns:
+            QueryChunksResponse with combined results
+        """
+        log.info(
+            f"WEAVIATE HYBRID SEARCH CALLED: query='{query_string}', embedding_shape={embedding.shape}, k={k}, threshold={score_threshold}, reranker={reranker_type}"
+        )
+        sanitized_collection_name = sanitize_collection_name(self.collection_name, weaviate_format=True)
+        collection = self.client.collections.get(sanitized_collection_name)
+
+        # Ranked (RRF) reranker fusion type
+        if reranker_type == RERANKER_TYPE_RRF:
+            rerank = HybridFusion.RANKED
+        # Relative score (Normalized) reranker fusion type
+        else:
+            rerank = HybridFusion.RELATIVE_SCORE
+
+        # Perform hybrid search using Weaviate's native hybrid search
+        results = collection.query.hybrid(
+            query=query_string,
+            alpha=0.5,  # Range <0, 1>, where 0.5 will equally favor vector and keyword search
+            vector=embedding.tolist(),
+            limit=k,
+            fusion_type=rerank,
+            return_metadata=wvc.query.MetadataQuery(score=True),
+        )
+
+        chunks = []
+        scores = []
+        for doc in results.objects:
+            chunk_json = doc.properties["chunk_content"]
+            try:
+                chunk_dict = json.loads(chunk_json)
+                chunk = Chunk(**chunk_dict)
+            except Exception:
+                log.exception(f"Failed to parse document: {chunk_json}")
+                continue
+
+            score = doc.metadata.score if doc.metadata.score is not None else 0.0
+            if score < score_threshold:
+                continue
+
+            log.info(f"Document {chunk.metadata.get('document_id')} has score {score}")
+            chunks.append(chunk)
+            scores.append(score)
+
+        log.info(f"WEAVIATE HYBRID SEARCH RESULTS: Found {len(chunks)} chunks with scores {scores}")
+        return QueryChunksResponse(chunks=chunks, scores=scores)
 
 
 class WeaviateVectorIOAdapter(

llama_stack/providers/utils/memory/vector_store.py

@@ -50,6 +50,7 @@ class ChunkForDeletion(BaseModel):
 # Constants for reranker types
 RERANKER_TYPE_RRF = "rrf"
 RERANKER_TYPE_WEIGHTED = "weighted"
+RERANKER_TYPE_NORMALIZED = "normalized"
 
 
 def parse_pdf(data: bytes) -> str:
@@ -325,6 +326,8 @@ class VectorDBWithIndex:
                 weights = ranker.get("params", {}).get("weights", [0.5, 0.5])
                 reranker_type = RERANKER_TYPE_WEIGHTED
                 reranker_params = {"alpha": weights[0] if len(weights) > 0 else 0.5}
+            elif strategy == "normalized":
+                reranker_type = RERANKER_TYPE_NORMALIZED
             else:
                 reranker_type = RERANKER_TYPE_RRF
                 k_value = ranker.get("params", {}).get("k", 60.0)

pyproject.toml

@@ -25,8 +25,8 @@ classifiers = [
 ]
 dependencies = [
     "aiohttp",
-    "fastapi>=0.115.0,<1.0",                  # server
+    "fastapi>=0.115.0,<1.0", # server
-    "fire",                                   # for MCP in LLS client
+    "fire", # for MCP in LLS client
     "httpx",
     "huggingface-hub>=0.34.0,<1.0",
     "jinja2>=3.1.6",
@@ -43,12 +43,13 @@ dependencies = [
     "tiktoken",
     "pillow",
     "h11>=0.16.0",
-    "python-multipart>=0.0.20",               # For fastapi Form
+    "python-multipart>=0.0.20", # For fastapi Form
-    "uvicorn>=0.34.0",                        # server
+    "uvicorn>=0.34.0", # server
-    "opentelemetry-sdk>=1.30.0",              # server
+    "opentelemetry-sdk>=1.30.0", # server
     "opentelemetry-exporter-otlp-proto-http>=1.30.0", # server
-    "aiosqlite>=0.21.0",                      # server - for metadata store
+    "aiosqlite>=0.21.0", # server - for metadata store
-    "asyncpg",                                # for metadata store
+    "asyncpg", # for metadata store
+    "weaviate-client>=4.16.5",
 ]
 
 [project.optional-dependencies]

tests/integration/vector_io/test_openai_vector_stores.py

@@ -22,16 +22,16 @@ def skip_if_provider_doesnt_support_openai_vector_stores(client_with_models):
     vector_io_providers = [p for p in client_with_models.providers.list() if p.api == "vector_io"]
     for p in vector_io_providers:
         if p.provider_type in [
-            "inline::faiss",
-            "inline::sqlite-vec",
-            "inline::milvus",
             "inline::chromadb",
-            "remote::pgvector",
+            "inline::faiss",
-            "remote::chromadb",
+            "inline::milvus",
-            "remote::qdrant",
             "inline::qdrant",
-            "remote::weaviate",
+            "inline::sqlite-vec",
+            "remote::chromadb",
             "remote::milvus",
+            "remote::pgvector",
+            "remote::qdrant",
+            "remote::weaviate",
         ]:
             return
 
@@ -47,23 +47,25 @@ def skip_if_provider_doesnt_support_openai_vector_stores_search(client_with_mode
             "inline::milvus",
             "inline::chromadb",
             "inline::qdrant",
-            "remote::pgvector",
             "remote::chromadb",
-            "remote::weaviate",
-            "remote::qdrant",
             "remote::milvus",
+            "remote::pgvector",
+            "remote::qdrant",
+            "remote::weaviate",
         ],
         "keyword": [
+            "inline::milvus",
             "inline::sqlite-vec",
             "remote::milvus",
-            "inline::milvus",
             "remote::pgvector",
+            "remote::weaviate",
         ],
         "hybrid": [
-            "inline::sqlite-vec",
             "inline::milvus",
+            "inline::sqlite-vec",
             "remote::milvus",
             "remote::pgvector",
+            "remote::weaviate",
         ],
     }
     supported_providers = search_mode_support.get(search_mode, [])

tests/unit/providers/vector_io/conftest.py

@@ -26,13 +26,15 @@ from llama_stack.providers.remote.vector_io.milvus.milvus import MilvusIndex, Mi
 from llama_stack.providers.remote.vector_io.pgvector.config import PGVectorVectorIOConfig
 from llama_stack.providers.remote.vector_io.pgvector.pgvector import PGVectorIndex, PGVectorVectorIOAdapter
 from llama_stack.providers.remote.vector_io.qdrant.qdrant import QdrantVectorIOAdapter
+from llama_stack.providers.remote.vector_io.weaviate.config import WeaviateVectorIOConfig
+from llama_stack.providers.remote.vector_io.weaviate.weaviate import WeaviateIndex, WeaviateVectorIOAdapter
 
 EMBEDDING_DIMENSION = 384
 COLLECTION_PREFIX = "test_collection"
 MILVUS_ALIAS = "test_milvus"
 
 
-@pytest.fixture(params=["milvus", "sqlite_vec", "faiss", "chroma", "pgvector"])
+@pytest.fixture(params=["milvus", "sqlite_vec", "faiss", "chroma", "pgvector", "weaviate"])
 def vector_provider(request):
     return request.param
 
@@ -446,6 +448,75 @@ async def pgvector_vec_adapter(mock_inference_api, embedding_dimension):
 
                         yield adapter
                         await adapter.shutdown()
+def weaviate_vec_db_path():
+    return "localhost:8080"
+
+
+@pytest.fixture
+async def weaviate_vec_index(weaviate_vec_db_path, embedding_dimension):
+    import uuid
+
+    import weaviate
+
+    # Connect to local Weaviate instance
+    client = weaviate.connect_to_local(
+        host="localhost",
+        port=8080,
+    )
+
+    collection_name = f"{COLLECTION_PREFIX}_{uuid.uuid4()}"
+    index = WeaviateIndex(client=client, collection_name=collection_name)
+
+    # Create the collection for this test
+    import weaviate.classes as wvc
+    from weaviate.collections.classes.config import _CollectionConfig
+
+    from llama_stack.providers.utils.vector_io.vector_utils import sanitize_collection_name
+
+    sanitized_name = sanitize_collection_name(collection_name, weaviate_format=True)
+    collection_config = _CollectionConfig(
+        name=sanitized_name,
+        vectorizer_config=wvc.config.Configure.Vectorizer.none(),
+        properties=[
+            wvc.config.Property(
+                name="chunk_content",
+                data_type=wvc.config.DataType.TEXT,
+            ),
+        ],
+    )
+    if not client.collections.exists(sanitized_name):
+        client.collections.create_from_config(collection_config)
+
+    yield index
+    await index.delete()
+    client.close()
+
+
+@pytest.fixture
+async def weaviate_vec_adapter(weaviate_vec_db_path, mock_inference_api, embedding_dimension):
+    config = WeaviateVectorIOConfig(
+        weaviate_cluster_url=weaviate_vec_db_path,
+        weaviate_api_key=None,
+        kvstore=SqliteKVStoreConfig(),
+    )
+    adapter = WeaviateVectorIOAdapter(
+        config=config,
+        inference_api=mock_inference_api,
+        files_api=None,
+    )
+    collection_id = f"weaviate_test_collection_{random.randint(1, 1_000_000)}"
+    await adapter.initialize()
+    await adapter.register_vector_db(
+        VectorDB(
+            identifier=collection_id,
+            provider_id="test_provider",
+            embedding_model="test_model",
+            embedding_dimension=embedding_dimension,
+        )
+    )
+    adapter.test_collection_id = collection_id
+    yield adapter
+    await adapter.shutdown()
 
 
 @pytest.fixture
@@ -457,6 +528,7 @@ def vector_io_adapter(vector_provider, request):
         "chroma": "chroma_vec_adapter",
         "qdrant": "qdrant_vec_adapter",
         "pgvector": "pgvector_vec_adapter",
+        "weaviate": "weaviate_vec_adapter",
     }
     return request.getfixturevalue(vector_provider_dict[vector_provider])
 

tests/unit/providers/vector_io/remote/test_milvus.py

@@ -23,13 +23,13 @@ pymilvus_mock.AnnSearchRequest = MagicMock
 with patch.dict("sys.modules", {"pymilvus": pymilvus_mock}):
     from llama_stack.providers.remote.vector_io.milvus.milvus import MilvusIndex
 
-# This test is a unit test for the MilvusVectorIOAdapter class. This should only contain
+# This test is a unit test for the MilvusIndex class. This should only contain
 # tests which are specific to this class. More general (API-level) tests should be placed in
 # tests/integration/vector_io/
 #
 # How to run this test:
 #
-# pytest tests/unit/providers/vector_io/test_milvus.py \
+# pytest tests/unit/providers/vector_io/remote/test_milvus.py \
 # -v -s --tb=short --disable-warnings --asyncio-mode=auto
 
 MILVUS_PROVIDER = "milvus"
@@ -324,3 +324,6 @@ async def test_query_hybrid_search_default_rrf(
     call_args = mock_milvus_client.hybrid_search.call_args
     ranker = call_args[1]["ranker"]
     assert ranker is not None
+
+
+# TODO: Write tests for the MilvusVectorIOAdapter class.

tests/unit/providers/vector_io/remote/test_weaviate.py

@@ -0,0 +1,269 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from unittest.mock import ANY, MagicMock, patch
+
+import numpy as np
+import pytest
+
+from llama_stack.apis.vector_io import QueryChunksResponse
+
+# Mock the Weaviate client
+weaviate_mock = MagicMock()
+
+# Apply the mock before importing WeaviateIndex
+with patch.dict("sys.modules", {"weaviate": weaviate_mock}):
+    from llama_stack.providers.remote.vector_io.weaviate.weaviate import WeaviateIndex
+
+# This test is a unit test for the WeaviateIndex class. This should only contain
+# tests which are specific to this class. More general (API-level) tests should be placed in
+# tests/integration/vector_io/
+#
+# How to run this test:
+#
+# pytest tests/unit/providers/vector_io/remote/test_weaviate.py \
+# -v -s --tb=short --disable-warnings --asyncio-mode=auto
+
+WEAVIATE_PROVIDER = "weaviate"
+
+
+@pytest.fixture
+async def mock_weaviate_client() -> MagicMock:
+    """Create a mock Weaviate client with common method behaviors."""
+    mock_client = MagicMock()
+    mock_collection = MagicMock()
+
+    # Mock collection data operations
+    mock_collection.data.insert_many.return_value = None
+    mock_collection.data.delete_many.return_value = None
+
+    # Mock collection search operations
+    mock_collection.query.near_vector.return_value = None
+    mock_collection.query.bm25.return_value = None
+    mock_collection.query.hybrid.return_value = None
+    mock_results = MagicMock()
+    mock_results.objects = [MagicMock(), MagicMock()]
+    mock_collection.query.near_vector.return_value = mock_results
+
+    # Mock client collection operations
+    mock_client.collections.get.return_value = mock_collection
+    mock_client.collections.exists.return_value = True
+    mock_client.collections.delete.return_value = None
+
+    # Mock client close operation
+    mock_client.close.return_value = None
+
+    return mock_client
+
+
+@pytest.fixture
+async def weaviate_index(mock_weaviate_client):
+    """Create a WeaviateIndex with mocked client."""
+    index = WeaviateIndex(client=mock_weaviate_client, collection_name="Testcollection")
+    yield index
+    # No real cleanup needed since we're using mocks
+
+
+async def test_add_chunks(weaviate_index, sample_chunks, sample_embeddings, mock_weaviate_client):
+    # Setup: Add chunks first
+    await weaviate_index.add_chunks(sample_chunks, sample_embeddings)
+
+    # Assert
+    mock_weaviate_client.collections.get.assert_called_once_with("Testcollection")
+    mock_weaviate_client.collections.get.return_value.data.insert_many.assert_called_once()
+
+    # Verify the insert call had the right number of chunks
+    data_objects, _ = mock_weaviate_client.collections.get.return_value.data.insert_many.call_args
+    assert len(data_objects[0]) == len(sample_chunks)
+
+
+async def test_query_chunks_vector(
+    weaviate_index, sample_chunks, sample_embeddings, embedding_dimension, mock_weaviate_client
+):
+    # Setup: Add chunks first
+    await weaviate_index.add_chunks(sample_chunks, sample_embeddings)
+
+    # Create mock objects that match Weaviate's response structure
+    mock_objects = []
+    for i, chunk in enumerate(sample_chunks[:2]):  # Return first 2 chunks
+        mock_obj = MagicMock()
+        mock_obj.properties = {"chunk_content": chunk.model_dump_json()}
+        mock_obj.metadata.distance = 0.1 + i * 0.1  # Mock distances
+        mock_objects.append(mock_obj)
+
+    mock_results = MagicMock()
+    mock_results.objects = mock_objects
+    mock_weaviate_client.collections.get.return_value.query.near_vector.return_value = mock_results
+
+    # Test vector search
+    query_embedding = np.random.rand(embedding_dimension).astype(np.float32)
+    response = await weaviate_index.query_vector(query_embedding, k=2, score_threshold=0.0)
+
+    assert isinstance(response, QueryChunksResponse)
+    assert len(response.chunks) == 2
+    assert len(response.scores) == 2
+    mock_weaviate_client.collections.get.return_value.query.near_vector.assert_called_once_with(
+        near_vector=query_embedding.tolist(),
+        limit=2,
+        return_metadata=ANY,
+    )
+
+
+async def test_query_chunks_keyword_search(weaviate_index, sample_chunks, sample_embeddings, mock_weaviate_client):
+    await weaviate_index.add_chunks(sample_chunks, sample_embeddings)
+
+    # Find chunks that contain "Sentence 5"
+    matching_chunks = [chunk for chunk in sample_chunks if "Sentence 5" in chunk.content]
+
+    # Create mock objects that match Weaviate's BM25 response structure
+    # Return the first 2 matching chunks
+    mock_objects = []
+    for i, chunk in enumerate(matching_chunks[:2]):
+        mock_obj = MagicMock()
+        mock_obj.properties = {"chunk_content": chunk.model_dump_json()}
+        mock_obj.metadata.score = 0.9 - i * 0.1
+        mock_objects.append(mock_obj)
+
+    mock_results = MagicMock()
+    mock_results.objects = mock_objects
+    mock_weaviate_client.collections.get.return_value.query.bm25.return_value = mock_results
+
+    # Test keyword search
+    query_string = "Sentence 5"
+    response = await weaviate_index.query_keyword(query_string=query_string, k=2, score_threshold=0.0)
+
+    assert isinstance(response, QueryChunksResponse)
+    assert len(response.chunks) == 2
+    assert len(response.scores) == 2
+    # Verify that the returned chunks contain the search term
+    assert all("Sentence 5" in chunk.content for chunk in response.chunks)
+    mock_weaviate_client.collections.get.return_value.query.bm25.assert_called_once_with(
+        query=query_string,
+        limit=2,
+        return_metadata=ANY,
+    )
+
+
+async def test_delete_collection(weaviate_index, mock_weaviate_client):
+    # Test collection deletion (when chunk_ids is None, it deletes the entire collection)
+    mock_weaviate_client.collections.exists.return_value = True
+
+    await weaviate_index.delete()
+
+    mock_weaviate_client.collections.exists.assert_called_once_with("Testcollection")
+    mock_weaviate_client.collections.delete.assert_called_once_with("Testcollection")
+
+
+async def test_delete_chunks(weaviate_index, mock_weaviate_client):
+    # Test deleting specific chunks using ChunkForDeletion objects
+    from llama_stack.providers.utils.memory.vector_store import ChunkForDeletion
+
+    chunks_for_deletion = [
+        ChunkForDeletion(chunk_id="chunk-1", document_id="doc-1"),
+        ChunkForDeletion(chunk_id="chunk-2", document_id="doc-1"),
+        ChunkForDeletion(chunk_id="chunk-3", document_id="doc-2"),
+    ]
+
+    await weaviate_index.delete_chunks(chunks_for_deletion)
+
+    mock_weaviate_client.collections.get.assert_called_once_with("Testcollection")
+    mock_weaviate_client.collections.get.return_value.data.delete_many.assert_called_once()
+
+
+async def test_query_hybrid_rrf(
+    weaviate_index, sample_chunks, sample_embeddings, embedding_dimension, mock_weaviate_client
+):
+    # Test hybrid search with RRF reranking
+    from weaviate.classes.query import HybridFusion
+
+    from llama_stack.providers.utils.memory.vector_store import RERANKER_TYPE_RRF
+
+    await weaviate_index.add_chunks(sample_chunks, sample_embeddings)
+
+    # Find chunks that contain "Sentence 5"
+    matching_chunks = [chunk for chunk in sample_chunks if "Sentence 5" in chunk.content]
+
+    # Create mock objects for hybrid search response
+    mock_objects = []
+    for i, chunk in enumerate(matching_chunks[:2]):
+        mock_obj = MagicMock()
+        mock_obj.properties = {"chunk_content": chunk.model_dump_json()}
+        mock_obj.metadata.score = 0.85 + i * 0.05
+        mock_objects.append(mock_obj)
+
+    mock_results = MagicMock()
+    mock_results.objects = mock_objects
+    mock_weaviate_client.collections.get.return_value.query.hybrid.return_value = mock_results
+
+    # Test hybrid search with RRF
+    query_string = "Sentence 5"
+    query_embedding = np.random.rand(embedding_dimension).astype(np.float32)
+    response = await weaviate_index.query_hybrid(
+        embedding=query_embedding, query_string=query_string, k=2, score_threshold=0.0, reranker_type=RERANKER_TYPE_RRF
+    )
+
+    assert isinstance(response, QueryChunksResponse)
+    assert len(response.chunks) == 2
+    assert len(response.scores) == 2
+    assert all("Sentence 5" in chunk.content for chunk in response.chunks)
+
+    # Verify the hybrid method was called with correct parameters
+    mock_weaviate_client.collections.get.return_value.query.hybrid.assert_called_once_with(
+        query=query_string,
+        alpha=0.5,
+        vector=query_embedding.tolist(),
+        limit=2,
+        fusion_type=HybridFusion.RANKED,
+        return_metadata=ANY,
+    )
+
+
+async def test_query_hybrid_normalized(
+    weaviate_index, sample_chunks, sample_embeddings, embedding_dimension, mock_weaviate_client
+):
+    from weaviate.classes.query import HybridFusion
+
+    await weaviate_index.add_chunks(sample_chunks, sample_embeddings)
+
+    # Find chunks that contain "Sentence 3" for different results
+    matching_chunks = [chunk for chunk in sample_chunks if "Sentence 3" in chunk.content]
+
+    # Create mock objects for hybrid search response
+    mock_objects = []
+    for i, chunk in enumerate(matching_chunks[:2]):
+        mock_obj = MagicMock()
+        mock_obj.properties = {"chunk_content": chunk.model_dump_json()}
+        mock_obj.metadata.score = 0.75 + i * 0.1  # Mock hybrid scores
+        mock_objects.append(mock_obj)
+
+    mock_results = MagicMock()
+    mock_results.objects = mock_objects
+    mock_weaviate_client.collections.get.return_value.query.hybrid.return_value = mock_results
+
+    # Test hybrid search with normalized reranking
+    query_string = "Sentence 3"
+    query_embedding = np.random.rand(embedding_dimension).astype(np.float32)
+    response = await weaviate_index.query_hybrid(
+        embedding=query_embedding, query_string=query_string, k=2, score_threshold=0.0, reranker_type="normalized"
+    )
+
+    assert isinstance(response, QueryChunksResponse)
+    assert len(response.chunks) == 2
+    assert len(response.scores) == 2
+    assert all("Sentence 3" in chunk.content for chunk in response.chunks)
+
+    # Verify the hybrid method was called with correct parameters
+    mock_weaviate_client.collections.get.return_value.query.hybrid.assert_called_once_with(
+        query=query_string,
+        alpha=0.5,
+        vector=query_embedding.tolist(),
+        limit=2,
+        fusion_type=HybridFusion.RELATIVE_SCORE,
+        return_metadata=ANY,
+    )
+
+
+# TODO: Write tests for the WeaviateVectorIOAdapter class.

uv.lock

@@ -1777,6 +1777,7 @@ dependencies = [
     { name = "termcolor" },
     { name = "tiktoken" },
     { name = "uvicorn" },
+    { name = "weaviate-client" },
 ]
 
 [package.optional-dependencies]
@@ -1904,6 +1905,7 @@ requires-dist = [
     { name = "termcolor" },
     { name = "tiktoken" },
     { name = "uvicorn", specifier = ">=0.34.0" },
+    { name = "weaviate-client", specifier = ">=4.16.5" },
 ]
 provides-extras = ["ui"]