Files
Claude-Code-Workflow/codex-lens/tests/test_ann_index.py
catlog22 e21d801523 feat: Add multi-type embedding backends for cascade retrieval
- Implemented BinaryEmbeddingBackend for fast coarse filtering using 256-dimensional binary vectors.
- Developed DenseEmbeddingBackend for high-precision dense vectors (2048 dimensions) for reranking.
- Created CascadeEmbeddingBackend to combine binary and dense embeddings for two-stage retrieval.
- Introduced utility functions for embedding conversion and distance computation.

chore: Migration 010 - Add multi-vector storage support

- Added 'chunks' table to support multi-vector embeddings for cascade retrieval.
- Included new columns: embedding_binary (256-dim) and embedding_dense (2048-dim) for efficient storage.
- Implemented upgrade and downgrade functions to manage schema changes and data migration.
2026-01-02 10:52:43 +08:00

744 lines
25 KiB
Python

"""Tests for ANN (Approximate Nearest Neighbor) index using HNSW."""
import tempfile
from pathlib import Path
from unittest.mock import patch
import pytest
# Skip all tests if semantic dependencies not available
pytest.importorskip("numpy")
def _hnswlib_available() -> bool:
"""Check if hnswlib is available."""
try:
import hnswlib
return True
except ImportError:
return False
class TestANNIndex:
"""Test suite for ANNIndex class."""
@pytest.fixture
def temp_db(self):
"""Create a temporary database file."""
with tempfile.TemporaryDirectory() as tmpdir:
yield Path(tmpdir) / "_index.db"
@pytest.fixture
def sample_vectors(self):
"""Generate sample vectors for testing."""
import numpy as np
np.random.seed(42)
# 100 vectors of dimension 384 (matches fast model)
return np.random.randn(100, 384).astype(np.float32)
@pytest.fixture
def sample_ids(self):
"""Generate sample IDs."""
return list(range(1, 101))
def test_import_check(self):
"""Test that HNSWLIB_AVAILABLE flag is set correctly."""
try:
from codexlens.semantic.ann_index import HNSWLIB_AVAILABLE
# Should be True if hnswlib is installed, False otherwise
assert isinstance(HNSWLIB_AVAILABLE, bool)
except ImportError:
pytest.skip("ann_index module not available")
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_create_index(self, temp_db):
"""Test creating a new ANN index."""
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
assert index.dim == 384
assert index.count() == 0
assert not index.is_loaded
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_add_vectors(self, temp_db, sample_vectors, sample_ids):
"""Test adding vectors to the index."""
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
index.add_vectors(sample_ids, sample_vectors)
assert index.count() == 100
assert index.is_loaded
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_search(self, temp_db, sample_vectors, sample_ids):
"""Test searching for similar vectors."""
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
index.add_vectors(sample_ids, sample_vectors)
# Search for the first vector - should find itself
query = sample_vectors[0]
ids, distances = index.search(query, top_k=5)
assert len(ids) == 5
assert len(distances) == 5
# First result should be the query vector itself (or very close)
assert ids[0] == 1 # ID of first vector
assert distances[0] < 0.01 # Very small distance (almost identical)
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_save_and_load(self, temp_db, sample_vectors, sample_ids):
"""Test saving and loading index from disk."""
from codexlens.semantic.ann_index import ANNIndex
# Create and save index
index1 = ANNIndex(temp_db, dim=384)
index1.add_vectors(sample_ids, sample_vectors)
index1.save()
# Check that file was created (new naming: {db_stem}_vectors.hnsw)
hnsw_path = temp_db.parent / f"{temp_db.stem}_vectors.hnsw"
assert hnsw_path.exists()
# Load in new instance
index2 = ANNIndex(temp_db, dim=384)
loaded = index2.load()
assert loaded is True
assert index2.count() == 100
assert index2.is_loaded
# Verify search still works
query = sample_vectors[0]
ids, distances = index2.search(query, top_k=5)
assert ids[0] == 1
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_load_nonexistent(self, temp_db):
"""Test loading when index file doesn't exist."""
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
loaded = index.load()
assert loaded is False
assert not index.is_loaded
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_remove_vectors(self, temp_db, sample_vectors, sample_ids):
"""Test removing vectors from the index."""
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
index.add_vectors(sample_ids, sample_vectors)
# Remove first 10 vectors
index.remove_vectors(list(range(1, 11)))
# Search for removed vector - should not be in results
query = sample_vectors[0]
ids, distances = index.search(query, top_k=5)
# ID 1 should not be in results (soft deleted)
assert 1 not in ids
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_incremental_add(self, temp_db):
"""Test adding vectors incrementally."""
import numpy as np
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
# Add first batch
vectors1 = np.random.randn(50, 384).astype(np.float32)
index.add_vectors(list(range(1, 51)), vectors1)
assert index.count() == 50
# Add second batch
vectors2 = np.random.randn(50, 384).astype(np.float32)
index.add_vectors(list(range(51, 101)), vectors2)
assert index.count() == 100
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_search_empty_index(self, temp_db):
"""Test searching an empty index."""
import numpy as np
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
query = np.random.randn(384).astype(np.float32)
ids, distances = index.search(query, top_k=5)
assert ids == []
assert distances == []
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_invalid_dimension(self, temp_db, sample_vectors, sample_ids):
"""Test adding vectors with wrong dimension."""
import numpy as np
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
# Try to add vectors with wrong dimension
wrong_vectors = np.random.randn(10, 768).astype(np.float32)
with pytest.raises(ValueError, match="dimension"):
index.add_vectors(list(range(1, 11)), wrong_vectors)
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_auto_resize(self, temp_db):
"""Test that index automatically resizes when capacity is exceeded."""
import numpy as np
from codexlens.semantic.ann_index import ANNIndex
index = ANNIndex(temp_db, dim=384)
# Override initial capacity to test resize
index._max_elements = 100
# Add more vectors than initial capacity
vectors = np.random.randn(150, 384).astype(np.float32)
index.add_vectors(list(range(1, 151)), vectors)
assert index.count() == 150
assert index._max_elements >= 150
class TestVectorStoreWithANN:
"""Test VectorStore integration with ANN index."""
@pytest.fixture
def temp_db(self):
"""Create a temporary database file."""
with tempfile.TemporaryDirectory(ignore_cleanup_errors=True) as tmpdir:
yield Path(tmpdir) / "_index.db"
@pytest.fixture
def sample_chunks(self):
"""Create sample semantic chunks with embeddings."""
import numpy as np
from codexlens.entities import SemanticChunk
np.random.seed(42)
chunks = []
for i in range(10):
chunk = SemanticChunk(
content=f"def function_{i}(): pass",
metadata={"symbol_name": f"function_{i}", "symbol_kind": "function"},
)
chunk.embedding = np.random.randn(384).astype(np.float32).tolist()
chunks.append(chunk)
return chunks
def test_vector_store_with_ann(self, temp_db, sample_chunks):
"""Test VectorStore using ANN index for search."""
from codexlens.semantic.vector_store import VectorStore, HNSWLIB_AVAILABLE
store = VectorStore(temp_db)
# Add chunks
ids = store.add_chunks(sample_chunks, "test.py")
assert len(ids) == 10
# Check ANN status
if HNSWLIB_AVAILABLE:
assert store.ann_available or store.ann_count >= 0
# Search
query_embedding = sample_chunks[0].embedding
results = store.search_similar(query_embedding, top_k=5)
assert len(results) <= 5
if results:
# First result should have high similarity
assert results[0].score > 0.9
def test_vector_store_rebuild_ann(self, temp_db, sample_chunks):
"""Test rebuilding ANN index from SQLite data."""
from codexlens.semantic.vector_store import VectorStore, HNSWLIB_AVAILABLE
if not HNSWLIB_AVAILABLE:
pytest.skip("hnswlib not installed")
store = VectorStore(temp_db)
# Add chunks
store.add_chunks(sample_chunks, "test.py")
# Rebuild ANN index
count = store.rebuild_ann_index()
assert count == 10
# Verify search works
query_embedding = sample_chunks[0].embedding
results = store.search_similar(query_embedding, top_k=5)
assert len(results) > 0
def test_vector_store_delete_updates_ann(self, temp_db, sample_chunks):
"""Test that deleting chunks updates ANN index."""
from codexlens.semantic.vector_store import VectorStore, HNSWLIB_AVAILABLE
if not HNSWLIB_AVAILABLE:
pytest.skip("hnswlib not installed")
store = VectorStore(temp_db)
# Add chunks for two files
store.add_chunks(sample_chunks[:5], "file1.py")
store.add_chunks(sample_chunks[5:], "file2.py")
initial_count = store.count_chunks()
assert initial_count == 10
# Delete one file's chunks
deleted = store.delete_file_chunks("file1.py")
assert deleted == 5
# Verify count
assert store.count_chunks() == 5
def test_vector_store_batch_add(self, temp_db, sample_chunks):
"""Test batch adding chunks from multiple files."""
from codexlens.semantic.vector_store import VectorStore
store = VectorStore(temp_db)
# Prepare chunks with paths
chunks_with_paths = [
(chunk, f"file{i % 3}.py")
for i, chunk in enumerate(sample_chunks)
]
# Batch add
ids = store.add_chunks_batch(chunks_with_paths)
assert len(ids) == 10
# Verify
assert store.count_chunks() == 10
def test_vector_store_fallback_search(self, temp_db, sample_chunks):
"""Test that search falls back to brute-force when ANN unavailable."""
from codexlens.semantic.vector_store import VectorStore
store = VectorStore(temp_db)
store.add_chunks(sample_chunks, "test.py")
# Force disable ANN
store._ann_index = None
# Search should still work (brute-force fallback)
query_embedding = sample_chunks[0].embedding
results = store.search_similar(query_embedding, top_k=5)
assert len(results) > 0
assert results[0].score > 0.9
class TestSearchAccuracy:
"""Test search accuracy comparing ANN vs brute-force."""
@pytest.fixture
def temp_db(self):
"""Create a temporary database file."""
with tempfile.TemporaryDirectory(ignore_cleanup_errors=True) as tmpdir:
yield Path(tmpdir) / "_index.db"
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_ann_vs_brute_force_recall(self, temp_db):
"""Test that ANN search has high recall compared to brute-force."""
import numpy as np
from codexlens.entities import SemanticChunk
from codexlens.semantic.vector_store import VectorStore
np.random.seed(42)
# Create larger dataset
chunks = []
for i in range(100):
chunk = SemanticChunk(
content=f"code block {i}",
metadata={"chunk_id": i},
)
chunk.embedding = np.random.randn(384).astype(np.float32).tolist()
chunks.append(chunk)
store = VectorStore(temp_db)
store.add_chunks(chunks, "test.py")
# Get brute-force results
store._ann_index = None # Force brute-force
store._invalidate_cache() # Clear cache to force refresh
query = chunks[0].embedding
bf_results = store.search_similar(query, top_k=10)
# Use chunk_id from metadata for comparison (more reliable than path+score)
bf_chunk_ids = {r.metadata.get("chunk_id") for r in bf_results}
# Rebuild ANN and get ANN results
store.rebuild_ann_index()
ann_results = store.search_similar(query, top_k=10)
ann_chunk_ids = {r.metadata.get("chunk_id") for r in ann_results}
# Calculate recall (how many brute-force results are in ANN results)
# ANN should find at least 80% of the same results
overlap = len(bf_chunk_ids & ann_chunk_ids)
recall = overlap / len(bf_chunk_ids) if bf_chunk_ids else 1.0
assert recall >= 0.8, f"ANN recall too low: {recall} (overlap: {overlap}, bf: {bf_chunk_ids}, ann: {ann_chunk_ids})"
class TestBinaryANNIndex:
"""Test suite for BinaryANNIndex class (Hamming distance-based search)."""
@pytest.fixture
def temp_db(self):
"""Create a temporary database file."""
with tempfile.TemporaryDirectory() as tmpdir:
yield Path(tmpdir) / "_index.db"
@pytest.fixture
def sample_binary_vectors(self):
"""Generate sample binary vectors for testing."""
import numpy as np
np.random.seed(42)
# 100 binary vectors of dimension 256 (packed as 32 bytes each)
binary_unpacked = (np.random.rand(100, 256) > 0.5).astype(np.uint8)
packed = [np.packbits(v).tobytes() for v in binary_unpacked]
return packed, binary_unpacked
@pytest.fixture
def sample_ids(self):
"""Generate sample IDs."""
return list(range(1, 101))
def test_create_binary_index(self, temp_db):
"""Test creating a new Binary ANN index."""
from codexlens.semantic.ann_index import BinaryANNIndex
index = BinaryANNIndex(temp_db, dim=256)
assert index.dim == 256
assert index.packed_dim == 32
assert index.count() == 0
assert not index.is_loaded
def test_invalid_dimension(self, temp_db):
"""Test that invalid dimensions are rejected."""
from codexlens.semantic.ann_index import BinaryANNIndex
# Dimension must be divisible by 8
with pytest.raises(ValueError, match="divisible by 8"):
BinaryANNIndex(temp_db, dim=255)
with pytest.raises(ValueError, match="positive"):
BinaryANNIndex(temp_db, dim=0)
def test_add_packed_vectors(self, temp_db, sample_binary_vectors, sample_ids):
"""Test adding packed binary vectors to the index."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
assert index.count() == 100
assert index.is_loaded
def test_add_numpy_vectors(self, temp_db, sample_binary_vectors, sample_ids):
"""Test adding unpacked numpy binary vectors."""
from codexlens.semantic.ann_index import BinaryANNIndex
import numpy as np
_, unpacked = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors_numpy(sample_ids, unpacked)
assert index.count() == 100
def test_search_packed(self, temp_db, sample_binary_vectors, sample_ids):
"""Test searching with packed binary query."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
# Search for the first vector - should find itself with distance 0
query = packed[0]
ids, distances = index.search(query, top_k=5)
assert len(ids) == 5
assert len(distances) == 5
# First result should be the query vector itself
assert ids[0] == 1
assert distances[0] == 0 # Hamming distance of 0 (identical)
def test_search_numpy(self, temp_db, sample_binary_vectors, sample_ids):
"""Test searching with unpacked numpy query."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, unpacked = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
# Search for the first vector using numpy interface
query = unpacked[0]
ids, distances = index.search_numpy(query, top_k=5)
assert len(ids) == 5
assert ids[0] == 1
assert distances[0] == 0
def test_search_batch(self, temp_db, sample_binary_vectors, sample_ids):
"""Test batch search with multiple queries."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
# Search for first 3 vectors
queries = packed[:3]
results = index.search_batch(queries, top_k=5)
assert len(results) == 3
# Each result should find itself first
for i, (ids, dists) in enumerate(results):
assert ids[0] == i + 1
assert dists[0] == 0
def test_hamming_distance_ordering(self, temp_db):
"""Test that results are ordered by Hamming distance."""
from codexlens.semantic.ann_index import BinaryANNIndex
import numpy as np
index = BinaryANNIndex(temp_db, dim=256)
# Create vectors with known Hamming distances from a query
query = np.zeros(256, dtype=np.uint8) # All zeros
v1 = np.zeros(256, dtype=np.uint8) # Distance 0
v2 = np.zeros(256, dtype=np.uint8); v2[:10] = 1 # Distance 10
v3 = np.zeros(256, dtype=np.uint8); v3[:50] = 1 # Distance 50
v4 = np.ones(256, dtype=np.uint8) # Distance 256
index.add_vectors_numpy([1, 2, 3, 4], np.array([v1, v2, v3, v4]))
query_packed = np.packbits(query).tobytes()
ids, distances = index.search(query_packed, top_k=4)
assert ids == [1, 2, 3, 4]
assert distances == [0, 10, 50, 256]
def test_save_and_load(self, temp_db, sample_binary_vectors, sample_ids):
"""Test saving and loading binary index from disk."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
# Create and save index
index1 = BinaryANNIndex(temp_db, dim=256)
index1.add_vectors(sample_ids, packed)
index1.save()
# Check that file was created
binary_path = temp_db.parent / f"{temp_db.stem}_binary_vectors.bin"
assert binary_path.exists()
# Load in new instance
index2 = BinaryANNIndex(temp_db, dim=256)
loaded = index2.load()
assert loaded is True
assert index2.count() == 100
assert index2.is_loaded
# Verify search still works
query = packed[0]
ids, distances = index2.search(query, top_k=5)
assert ids[0] == 1
assert distances[0] == 0
def test_load_nonexistent(self, temp_db):
"""Test loading when index file doesn't exist."""
from codexlens.semantic.ann_index import BinaryANNIndex
index = BinaryANNIndex(temp_db, dim=256)
loaded = index.load()
assert loaded is False
assert not index.is_loaded
def test_remove_vectors(self, temp_db, sample_binary_vectors, sample_ids):
"""Test removing vectors from the index."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
# Remove first 10 vectors
index.remove_vectors(list(range(1, 11)))
assert index.count() == 90
# Removed vectors should not be findable
query = packed[0]
ids, _ = index.search(query, top_k=100)
for removed_id in range(1, 11):
assert removed_id not in ids
def test_get_vector(self, temp_db, sample_binary_vectors, sample_ids):
"""Test retrieving a specific vector by ID."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
# Get existing vector
vec = index.get_vector(1)
assert vec == packed[0]
# Get non-existing vector
vec = index.get_vector(9999)
assert vec is None
def test_clear(self, temp_db, sample_binary_vectors, sample_ids):
"""Test clearing all vectors from the index."""
from codexlens.semantic.ann_index import BinaryANNIndex
packed, _ = sample_binary_vectors
index = BinaryANNIndex(temp_db, dim=256)
index.add_vectors(sample_ids, packed)
assert index.count() == 100
index.clear()
assert index.count() == 0
assert not index.is_loaded
def test_search_empty_index(self, temp_db):
"""Test searching an empty index."""
from codexlens.semantic.ann_index import BinaryANNIndex
import numpy as np
index = BinaryANNIndex(temp_db, dim=256)
query = np.packbits(np.zeros(256, dtype=np.uint8)).tobytes()
ids, distances = index.search(query, top_k=5)
assert ids == []
assert distances == []
def test_update_existing_vector(self, temp_db):
"""Test updating an existing vector with new data."""
from codexlens.semantic.ann_index import BinaryANNIndex
import numpy as np
index = BinaryANNIndex(temp_db, dim=256)
# Add initial vector
v1 = np.zeros(256, dtype=np.uint8)
index.add_vectors_numpy([1], v1.reshape(1, -1))
# Update with different vector
v2 = np.ones(256, dtype=np.uint8)
index.add_vectors_numpy([1], v2.reshape(1, -1))
# Count should still be 1
assert index.count() == 1
# Retrieved vector should be the updated one
stored = index.get_vector(1)
expected = np.packbits(v2).tobytes()
assert stored == expected
class TestCreateAnnIndexFactory:
"""Test suite for create_ann_index factory function."""
@pytest.fixture
def temp_db(self):
"""Create a temporary database file."""
with tempfile.TemporaryDirectory() as tmpdir:
yield Path(tmpdir) / "_index.db"
@pytest.mark.skipif(
not _hnswlib_available(),
reason="hnswlib not installed"
)
def test_create_hnsw_index(self, temp_db):
"""Test creating HNSW index via factory."""
from codexlens.semantic.ann_index import create_ann_index, ANNIndex
index = create_ann_index(temp_db, index_type="hnsw", dim=384)
assert isinstance(index, ANNIndex)
assert index.dim == 384
def test_create_binary_index(self, temp_db):
"""Test creating binary index via factory."""
from codexlens.semantic.ann_index import create_ann_index, BinaryANNIndex
index = create_ann_index(temp_db, index_type="binary", dim=256)
assert isinstance(index, BinaryANNIndex)
assert index.dim == 256
def test_create_binary_index_default_dim(self, temp_db):
"""Test that binary index defaults to 256 dim when dense default is used."""
from codexlens.semantic.ann_index import create_ann_index, BinaryANNIndex
# When dim=2048 (dense default) is passed with binary type,
# it should auto-adjust to 256
index = create_ann_index(temp_db, index_type="binary")
assert isinstance(index, BinaryANNIndex)
assert index.dim == 256
def test_invalid_index_type(self, temp_db):
"""Test that invalid index type raises error."""
from codexlens.semantic.ann_index import create_ann_index
with pytest.raises(ValueError, match="Invalid index_type"):
create_ann_index(temp_db, index_type="invalid")
def test_case_insensitive_index_type(self, temp_db):
"""Test that index_type is case-insensitive."""
from codexlens.semantic.ann_index import create_ann_index, BinaryANNIndex
index = create_ann_index(temp_db, index_type="BINARY", dim=256)
assert isinstance(index, BinaryANNIndex)