"""Performance regression tests for hashing implementation.
Validates that xxHash3-64 provides expected performance characteristics
compared to SHA-256 baseline (2x+ faster).
"""
import time
from pathlib import Path
import pytest
def test_hash_performance_10mb_file(tmp_path: Path):
"""Verify xxHash3-64 completes in <50ms for 10MB file.
This test validates the performance benefit of using xxHash3-64 instead
of SHA-256. SHA-256 would take ~100ms for this file size, so we verify
that xxHash3-64 completes in <50ms (2x+ speedup).
"""
from chunkhound.utils.hashing import compute_file_hash
# Create a 10MB test file
large_file = tmp_path / "large_test.py"
# Write realistic Python-like content to avoid compression artifacts
content = b"# Python code\n" + b"x = " + b"1234567890" * 1_000_000
large_file.write_bytes(content)
# Measure hash computation time
start = time.perf_counter()
hash_result = compute_file_hash(large_file)
elapsed = time.perf_counter() - start
# Verify hash format (16 hex characters for 64-bit hash)
assert len(hash_result) == 16, f"Expected 16 hex chars, got {len(hash_result)}"
assert all(c in "0123456789abcdef" for c in hash_result), (
f"Hash should be hex string, got: {hash_result}"
)
# Verify performance: should be <50ms (2x faster than SHA-256's ~100ms)
# Allow some slack for CI environments (100ms max)
assert elapsed < 0.1, (
f"Hash computation took {elapsed*1000:.1f}ms, expected <100ms. "
f"This may indicate a performance regression."
)
# Log actual performance for monitoring
print(f"\nxxHash3-64 performance: {elapsed*1000:.1f}ms for 10MB file")
def test_hash_format_consistency(tmp_path: Path):
"""Verify hash format is consistent (16 hex characters)."""
from chunkhound.utils.hashing import compute_file_hash
test_file = tmp_path / "test.py"
test_file.write_text("print('hello')\n")
hash1 = compute_file_hash(test_file)
hash2 = compute_file_hash(test_file)
# Same file should produce same hash
assert hash1 == hash2
# Verify format
assert len(hash1) == 16
assert all(c in "0123456789abcdef" for c in hash1)
def test_hash_detects_changes(tmp_path: Path):
"""Verify hash changes when file content changes."""
from chunkhound.utils.hashing import compute_file_hash
test_file = tmp_path / "test.py"
# Original content
test_file.write_text("print('hello')\n")
hash1 = compute_file_hash(test_file)
# Modified content
test_file.write_text("print('world')\n")
hash2 = compute_file_hash(test_file)
# Hashes should differ
assert hash1 != hash2, "Hash should change when file content changes"
def test_hash_handles_empty_file(tmp_path: Path):
"""Verify hash computation works for empty files."""
from chunkhound.utils.hashing import compute_file_hash
empty_file = tmp_path / "empty.py"
empty_file.write_text("")
hash_result = compute_file_hash(empty_file)
# Should return valid hash even for empty file
assert len(hash_result) == 16
assert all(c in "0123456789abcdef" for c in hash_result)
def test_hash_raises_on_directory(tmp_path: Path):
"""Verify hash computation raises ValueError for directories."""
from chunkhound.utils.hashing import compute_file_hash
test_dir = tmp_path / "test_directory"
test_dir.mkdir()
with pytest.raises(ValueError, match="Path must be a file"):
compute_file_hash(test_dir)
def test_hash_raises_on_nonexistent_file(tmp_path: Path):
"""Verify hash computation raises OSError for nonexistent files."""
from chunkhound.utils.hashing import compute_file_hash
nonexistent = tmp_path / "does_not_exist.py"
with pytest.raises((OSError, ValueError)):
compute_file_hash(nonexistent)
