392 lines
14 KiB
Python
392 lines
14 KiB
Python
# Copyright 2025-present the zvec project
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Tests for FTS + vector hybrid retrieval via multi-query with reranker."""
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from __future__ import annotations
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import pytest
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import zvec
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from zvec import (
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Collection,
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CollectionOption,
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DataType,
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Doc,
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FieldSchema,
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FtsIndexParam,
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HnswIndexParam,
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VectorSchema,
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)
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from zvec.extension.multi_vector_reranker import RrfReRanker, WeightedReRanker
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from zvec.model.param.query import Fts, Query
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DIM = 16
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# ==================== Fixtures ====================
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@pytest.fixture(scope="function")
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def hybrid_collection(tmp_path_factory) -> Collection:
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"""Collection with one vector field + one FTS field."""
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temp_dir = tmp_path_factory.mktemp("zvec_hybrid")
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collection_path = temp_dir / "hybrid_collection"
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schema = zvec.CollectionSchema(
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name="hybrid_test",
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fields=[
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FieldSchema("title", DataType.STRING, nullable=False),
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FieldSchema(
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"content",
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DataType.STRING,
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nullable=False,
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index_param=FtsIndexParam(
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tokenizer_name="standard",
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filters=["lowercase"],
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),
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),
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],
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vectors=[
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VectorSchema(
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"embedding",
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DataType.VECTOR_FP32,
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dimension=DIM,
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index_param=HnswIndexParam(),
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),
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],
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)
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coll = zvec.create_and_open(
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path=str(collection_path),
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schema=schema,
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option=CollectionOption(read_only=False, enable_mmap=True),
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)
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assert coll is not None
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try:
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yield coll
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finally:
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try:
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coll.destroy()
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except Exception as e:
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print(f"Warning: failed to destroy collection: {e}")
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def _make_docs() -> list[Doc]:
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"""Corpus with both text content and vectors.
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Docs 0-2: AI/ML topic, vectors clustered in one region.
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Docs 3-4: retrieval topic, vectors clustered in another region.
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Doc 5: unrelated topic.
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"""
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# AI cluster vectors
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ai_vec = [1.0] * 8 + [0.0] * 8
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# Retrieval cluster vectors
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ret_vec = [0.0] * 8 + [1.0] * 8
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# Unrelated vector
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other_vec = [0.5] * 16
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return [
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Doc(
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id="pk_0",
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fields={
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"title": "ML Intro",
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"content": "machine learning is a branch of artificial intelligence",
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},
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vectors={"embedding": ai_vec},
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),
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Doc(
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id="pk_1",
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fields={
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"title": "Deep Learning",
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"content": "deep learning uses neural networks for pattern recognition",
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},
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vectors={"embedding": [0.9] * 8 + [0.1] * 8},
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),
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Doc(
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id="pk_2",
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fields={
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"title": "NLP",
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"content": "natural language processing handles text with artificial intelligence",
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},
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vectors={"embedding": [0.8] * 8 + [0.2] * 8},
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),
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Doc(
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id="pk_3",
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fields={
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"title": "Search Engine",
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"content": "search engine uses inverted index for text retrieval",
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},
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vectors={"embedding": ret_vec},
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),
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Doc(
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id="pk_4",
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fields={
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"title": "Vector DB",
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"content": "vector database enables similarity retrieval and search",
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},
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vectors={"embedding": [0.1] * 8 + [0.9] * 8},
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),
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Doc(
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id="pk_5",
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fields={
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"title": "Cooking",
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"content": "baking bread requires flour water yeast and salt",
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},
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vectors={"embedding": other_vec},
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),
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]
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@pytest.fixture(scope="function")
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def hybrid_collection_with_docs(hybrid_collection: Collection) -> Collection:
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"""Hybrid collection pre-populated with test documents."""
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results = hybrid_collection.insert(_make_docs())
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assert all(r.ok() for r in results)
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return hybrid_collection
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# ==================== Tests ====================
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class TestFtsVectorHybridQuery:
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"""Test FTS + vector hybrid retrieval using multi-query with RRF reranker."""
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def test_hybrid_fts_and_vector_basic(self, hybrid_collection_with_docs: Collection):
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"""FTS + vector multi-query with RRF reranker returns results."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="retrieval")),
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Query(field_name="embedding", vector=[0.0] * 8 + [1.0] * 8),
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],
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topk=5,
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reranker=reranker,
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)
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assert len(result) > 0
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assert len(result) <= 5
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# Results should have scores
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for doc in result:
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assert doc.score > 0
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def test_hybrid_fts_and_vector_ranking(
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self, hybrid_collection_with_docs: Collection
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):
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"""Docs relevant in both FTS and vector should rank higher."""
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reranker = RrfReRanker(rank_constant=60)
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# FTS: "retrieval search" matches pk_3, pk_4
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# Vector: ret_vec cluster matches pk_3, pk_4
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# Both signals agree: pk_3 and pk_4 should rank top
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="retrieval search")),
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Query(field_name="embedding", vector=[0.0] * 8 + [1.0] * 8),
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],
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topk=5,
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reranker=reranker,
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)
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top_ids = {doc.id for doc in result[:3]}
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assert "pk_3" in top_ids or "pk_4" in top_ids
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def test_hybrid_scores_descending(self, hybrid_collection_with_docs: Collection):
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"""Hybrid query results must be sorted by score descending."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="intelligence")),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=6,
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reranker=reranker,
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)
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assert len(result) >= 2
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scores = [doc.score for doc in result]
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assert scores == sorted(scores, reverse=True)
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def test_hybrid_with_filter(self, hybrid_collection_with_docs: Collection):
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"""Hybrid query respects SQL filter."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="learning")),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=10,
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reranker=reranker,
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filter="title like '%Learning%'",
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)
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for doc in result:
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assert "Learning" in doc.fields["title"]
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def test_hybrid_fts_no_match_still_returns_vector_results(
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self, hybrid_collection_with_docs: Collection
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):
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"""When FTS matches nothing, vector results still appear."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(
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field_name="content",
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fts=Fts(match_string="nonexistent_term_xyz"),
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),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=5,
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reranker=reranker,
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)
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# Vector query alone should still produce results
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assert len(result) > 0
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def test_hybrid_query_string_syntax(self, hybrid_collection_with_docs: Collection):
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"""Hybrid query works with FTS query_string (advanced syntax)."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(
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field_name="content",
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fts=Fts(query_string="artificial AND intelligence"),
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),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=5,
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reranker=reranker,
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)
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assert len(result) > 0
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# pk_0 and pk_2 contain "artificial intelligence"
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hit_ids = {doc.id for doc in result}
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assert "pk_0" in hit_ids or "pk_2" in hit_ids
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class TestFtsVectorHybridValidation:
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"""Test validation rules for FTS + vector hybrid queries."""
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def test_hybrid_requires_reranker(self, hybrid_collection_with_docs: Collection):
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"""Multi-query with FTS + vector without reranker should raise."""
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with pytest.raises(ValueError, match="[Rr]eranker"):
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hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="learning")),
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Query(field_name="embedding", vector=[1.0] * DIM),
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],
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topk=5,
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)
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def test_duplicate_field_name_allowed(
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self, hybrid_collection_with_docs: Collection
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):
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"""Multi-query with duplicate field names is allowed and returns results."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="learning")),
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Query(field_name="content", fts=Fts(match_string="intelligence")),
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],
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topk=5,
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reranker=reranker,
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)
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assert len(result) > 0
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assert len(result) <= 5
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def test_multiple_vectors_allowed(self, hybrid_collection_with_docs: Collection):
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"""Two vector queries on the same field are allowed with a reranker."""
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reranker = RrfReRanker(rank_constant=60)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="embedding", vector=[1.0] * DIM),
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Query(field_name="embedding", vector=[0.5] * DIM),
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],
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topk=5,
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reranker=reranker,
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)
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assert len(result) > 0
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assert len(result) <= 5
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class TestFtsVectorHybridWeightedReranker:
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"""Test FTS + vector hybrid retrieval using WeightedReranker."""
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def test_weighted_reranker_fts_and_vector(
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self, hybrid_collection_with_docs: Collection
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):
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"""WeightedReranker correctly normalizes FTS scores alongside vector scores."""
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weights = [0.5, 0.5]
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reranker = WeightedReRanker(weights=weights)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="retrieval search")),
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Query(field_name="embedding", vector=[0.0] * 8 + [1.0] * 8),
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],
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topk=5,
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reranker=reranker,
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)
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assert len(result) > 0
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assert len(result) <= 5
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for doc in result:
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assert doc.score > 0
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def test_weighted_reranker_scores_descending(
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self, hybrid_collection_with_docs: Collection
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):
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"""WeightedReranker hybrid results are sorted by score descending."""
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weights = [0.4, 0.6]
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reranker = WeightedReRanker(weights=weights)
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result = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="intelligence")),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=6,
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reranker=reranker,
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)
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assert len(result) >= 2
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scores = [doc.score for doc in result]
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assert scores == sorted(scores, reverse=True)
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def test_weighted_reranker_fts_weight_influence(
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self, hybrid_collection_with_docs: Collection
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):
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"""Higher FTS weight should boost FTS-relevant docs in ranking."""
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# High FTS weight: FTS signal dominates
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weights_fts_heavy = [0.9, 0.1]
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reranker_fts = WeightedReRanker(weights=weights_fts_heavy)
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result_fts = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="retrieval")),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=5,
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reranker=reranker_fts,
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)
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# High vector weight: vector signal dominates
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weights_vec_heavy = [0.1, 0.9]
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reranker_vec = WeightedReRanker(weights=weights_vec_heavy)
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result_vec = hybrid_collection_with_docs.query(
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queries=[
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Query(field_name="content", fts=Fts(match_string="retrieval")),
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Query(field_name="embedding", vector=[1.0] * 8 + [0.0] * 8),
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],
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topk=5,
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reranker=reranker_vec,
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)
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# Both should return results
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assert len(result_fts) > 0
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assert len(result_vec) > 0
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# With FTS-heavy weight, FTS-relevant docs (pk_3, pk_4) should rank higher
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fts_top = [doc.id for doc in result_fts[:2]]
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vec_top = [doc.id for doc in result_vec[:2]]
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# The rankings should differ due to weight difference
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assert fts_top != vec_top or len(result_fts) == len(result_vec) == 1
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