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alibaba--zvec/python/tests/test_collection_fts_vector_hybrid.py
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2026-07-13 12:47:42 +08:00

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Python

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