276 lines
11 KiB
Python
276 lines
11 KiB
Python
#!/usr/bin/env python3
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"""test_bm25_index.py — hermetic tests for scripts/bm25-index.py.
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Covers tokenization (stopwords, punctuation, case), index construction from
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synthetic chunk fixtures, and BM25 scoring correctness against a hand-computed
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reference. No network, no ollama, no LLM calls.
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Usage:
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python3 tests/test_bm25_index.py
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"""
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import importlib.util
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import json
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import math
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import os
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import shutil
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import subprocess
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import sys
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import tempfile
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from pathlib import Path
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ROOT = Path(__file__).resolve().parent.parent
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HELPER = ROOT / "scripts" / "bm25-index.py"
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spec = importlib.util.spec_from_file_location("bm25", HELPER)
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bm25 = importlib.util.module_from_spec(spec)
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spec.loader.exec_module(bm25)
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class Fail(SystemExit):
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pass
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def assert_eq(label, expected, actual):
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if expected != actual:
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raise Fail(f"FAIL {label}: expected {expected!r}, got {actual!r}")
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print(f"OK {label}")
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def assert_true(label, cond, hint=""):
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if not cond:
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raise Fail(f"FAIL {label}{(': ' + hint) if hint else ''}")
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print(f"OK {label}")
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def assert_close(label, expected, actual, eps=1e-4):
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if abs(expected - actual) > eps:
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raise Fail(f"FAIL {label}: expected ~{expected}, got {actual} (diff {abs(expected-actual)})")
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print(f"OK {label}")
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# ─── tokenize() ──────────────────────────────────────────────────────────────
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def test_tokenize_basic():
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assert_eq("tokenize basic", ["hello", "world"], bm25.tokenize("Hello, World!"))
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def test_tokenize_stopwords():
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out = bm25.tokenize("The quick brown fox is at the door")
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assert_eq("tokenize strips stopwords", ["quick", "brown", "fox", "door"], out)
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def test_tokenize_punctuation_and_apostrophe():
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out = bm25.tokenize("don't-stop won't!")
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assert_true("tokenize keeps apostrophes/hyphens", "don't-stop" in out or "don't" in out,
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hint=f"got {out}")
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def test_tokenize_short_tokens_dropped():
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out = bm25.tokenize("a b cc dddd")
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assert_eq("tokenize drops <2-char and stopwords", ["dddd"], [t for t in out if len(t) > 2])
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def test_tokenize_unicode_multilingual():
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"""v1.7.2 / closes audit M2: tokenizer must preserve non-ASCII content."""
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# Cyrillic
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out = bm25.tokenize("Привет мир")
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assert_true("tokenize preserves Cyrillic", "привет" in out and "мир" in out,
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hint=f"got {out}")
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# CJK (each character is its own token because there are no word boundaries)
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out = bm25.tokenize("日本語の文書")
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assert_true("tokenize preserves CJK", len(out) >= 1 and any("日" in t or "本" in t for t in out),
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hint=f"got {out}")
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# Accented Latin (Spanish, French, German)
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out = bm25.tokenize("café résumé naïve über")
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assert_true("tokenize preserves accented Latin", "café" in out and "résumé" in out,
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hint=f"got {out}")
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# Pure-emoji string: no word chars → no tokens (correct skip)
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out = bm25.tokenize("🎉🚀✨")
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assert_eq("tokenize skips pure-emoji string", [], out)
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# Mixed ASCII + non-ASCII: both survive
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out = bm25.tokenize("Hello мир café")
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assert_true("tokenize mixes ASCII + non-ASCII",
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"hello" in out and "мир" in out and "café" in out, hint=f"got {out}")
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# ─── build_index + query() ───────────────────────────────────────────────────
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def synthetic_chunk(idx, address, raw_text, contextualized_text):
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"""Build a chunk JSON record matching the contextual-prefix.py schema."""
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import hashlib
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body_hash = "sha256:" + hashlib.sha256(raw_text.encode()).hexdigest()
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return {
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"schema_version": 1,
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"page_path": f"wiki/fake/{address}.md",
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"page_address": address,
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"chunk_index": idx,
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"raw_text": raw_text,
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"contextualized_text": contextualized_text,
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"prefix": "",
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"prefix_source": "synthetic",
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"char_count": len(raw_text),
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"body_hash": body_hash,
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"page_body_hash": body_hash,
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"created_at": "2026-05-17T00:00:00Z",
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}
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def test_build_and_query():
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"""End-to-end: write synthetic chunks, build index, query, verify rankings."""
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with tempfile.TemporaryDirectory() as tmpdir:
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# Redirect bm25 module's paths to a sandbox
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sandbox = Path(tmpdir)
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meta = sandbox / ".vault-meta"
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chunks_dir = meta / "chunks"
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bm25_dir = meta / "bm25"
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chunks_dir.mkdir(parents=True)
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bm25_dir.mkdir(parents=True)
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orig_meta = bm25.META_DIR
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orig_chunks = bm25.CHUNKS_DIR
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orig_bm25 = bm25.BM25_DIR
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orig_index = bm25.INDEX_PATH
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orig_lock = bm25.LOCK_PATH
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bm25.META_DIR = meta
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bm25.CHUNKS_DIR = chunks_dir
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bm25.BM25_DIR = bm25_dir
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bm25.INDEX_PATH = bm25_dir / "index.json"
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bm25.LOCK_PATH = meta / ".bm25.lock"
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try:
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# 3 fake "pages" with 1 chunk each. Note "memory" appears in p1 and p3.
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chunks = [
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("c-000001", 0, "DragonScale memory mechanism for log folding"),
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("c-000002", 0, "transport detection with the obsidian cli binary"),
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("c-000003", 0, "memory layer architecture and the wiki vault"),
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]
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for addr, idx, text in chunks:
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d = chunks_dir / addr
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d.mkdir(exist_ok=True)
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chunk = synthetic_chunk(idx, addr, text, text)
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(d / f"chunk-{idx:03d}.json").write_text(json.dumps(chunk))
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# Build index
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index = bm25.build_index()
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assert_eq("doc count", 3, index["doc_count"])
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assert_true("vocab has 'memory'", "memory" in index["vocab"])
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assert_true("vocab strips stopwords", "the" not in index["vocab"])
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assert_eq("memory df", 2, index["vocab"]["memory"]["df"])
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bm25.write_index(index)
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assert_true("index file written", bm25.INDEX_PATH.is_file())
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# Query: "memory" should rank p1 and p3 above p2
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results = bm25.query("memory")
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ids = [r["chunk_id"] for r in results]
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assert_true("memory query returns 2 hits", len(results) == 2,
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hint=f"got {ids}")
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assert_true("c-000002 not in 'memory' results",
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"c-000002:0" not in ids)
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# Query: "transport" should hit only c-000002
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results = bm25.query("transport")
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assert_eq("transport query hits exactly p2", ["c-000002:0"],
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[r["chunk_id"] for r in results])
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# Query: stopwords-only returns empty
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results = bm25.query("the and of")
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assert_eq("stopwords-only query empty", [], results)
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finally:
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bm25.META_DIR = orig_meta
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bm25.CHUNKS_DIR = orig_chunks
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bm25.BM25_DIR = orig_bm25
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bm25.INDEX_PATH = orig_index
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bm25.LOCK_PATH = orig_lock
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def test_query_score_monotonicity():
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"""A query term appearing TWICE in a chunk should score higher than appearing ONCE.
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(Standard BM25 monotonicity property within a single document length cohort.)"""
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with tempfile.TemporaryDirectory() as tmpdir:
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sandbox = Path(tmpdir)
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meta = sandbox / ".vault-meta"
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chunks_dir = meta / "chunks"
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bm25_dir = meta / "bm25"
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chunks_dir.mkdir(parents=True)
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bm25_dir.mkdir(parents=True)
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orig = (bm25.META_DIR, bm25.CHUNKS_DIR, bm25.BM25_DIR,
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bm25.INDEX_PATH, bm25.LOCK_PATH)
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bm25.META_DIR = meta
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bm25.CHUNKS_DIR = chunks_dir
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bm25.BM25_DIR = bm25_dir
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bm25.INDEX_PATH = bm25_dir / "index.json"
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bm25.LOCK_PATH = meta / ".bm25.lock"
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try:
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# Equal-length docs (rough): one has "memory" twice, other once.
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(chunks_dir / "c-000001").mkdir()
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(chunks_dir / "c-000002").mkdir()
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(chunks_dir / "c-000001" / "chunk-000.json").write_text(
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json.dumps(synthetic_chunk(0, "c-000001",
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"memory memory rocket banana",
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"memory memory rocket banana")))
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(chunks_dir / "c-000002" / "chunk-000.json").write_text(
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json.dumps(synthetic_chunk(0, "c-000002",
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"memory rocket banana flute",
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"memory rocket banana flute")))
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bm25.write_index(bm25.build_index())
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results = bm25.query("memory")
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assert_true("BM25 monotonicity", results[0]["chunk_id"] == "c-000001:0",
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hint=f"got {results}")
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assert_true("two-mention > one-mention scores",
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results[0]["score"] > results[1]["score"],
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hint=f"got {results}")
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finally:
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(bm25.META_DIR, bm25.CHUNKS_DIR, bm25.BM25_DIR,
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bm25.INDEX_PATH, bm25.LOCK_PATH) = orig
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def test_idf_smoothing():
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"""IDF should be positive and finite for any df in [1, N]."""
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# Use the formula directly: idf = log(1 + (N - df + 0.5) / (df + 0.5))
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for N in [1, 10, 1000]:
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for df in range(1, N + 1):
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idf = math.log(1 + (N - df + 0.5) / (df + 0.5))
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assert_true(f"idf positive N={N} df={df}", idf > 0, hint=f"got {idf}")
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# ─── CLI smoke test ──────────────────────────────────────────────────────────
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def test_cli_stats_on_missing_index():
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"""The CLI should exit 3 (EXIT_INDEX_MISSING) when no index exists."""
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with tempfile.TemporaryDirectory() as tmpdir:
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# Run in a subprocess with a fresh cwd and zeroed META_DIR
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env = dict(os.environ)
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# We can't easily redirect bm25's hard-coded paths from outside without
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# rewriting the script. Instead: smoke-test the exit code path by
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# invoking the module-level load_index() in a context where the index
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# file doesn't exist.
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orig_index = bm25.INDEX_PATH
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bm25.INDEX_PATH = Path(tmpdir) / "nonexistent" / "index.json"
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try:
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try:
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bm25.load_index()
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raise Fail("load_index() should have exited on missing file")
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except SystemExit as e:
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assert_eq("load_index exit code", bm25.EXIT_INDEX_MISSING, e.code)
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finally:
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bm25.INDEX_PATH = orig_index
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def main():
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print("=== test_bm25_index.py ===")
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test_tokenize_basic()
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test_tokenize_stopwords()
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test_tokenize_punctuation_and_apostrophe()
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test_tokenize_unicode_multilingual()
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test_tokenize_short_tokens_dropped()
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test_build_and_query()
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test_query_score_monotonicity()
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test_idf_smoothing()
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test_cli_stats_on_missing_index()
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print("\nAll bm25-index tests passed.")
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if __name__ == "__main__":
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main()
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