chore: import upstream snapshot with attribution

tests/test_minhash.py

@@ -0,0 +1,101 @@
+"""Tests for graphify/_minhash.py — MinHash sketch and band-LSH."""
+from __future__ import annotations
+import numpy as np
+import pytest
+from graphify._minhash import MinHash, MinHashLSH, _optimal_lsh_params
+
+
+def _minhash_for(text: str, num_perm: int = 128) -> MinHash:
+    m = MinHash(num_perm=num_perm)
+    for i in range(0, len(text) - 2):
+        m.update(text[i:i + 3].encode())
+    return m
+
+
+# ── MinHash ───────────────────────────────────────────────────────────────────
+
+def test_identical_texts_produce_identical_hashvalues():
+    a = _minhash_for("graphextractor")
+    b = _minhash_for("graphextractor")
+    assert np.array_equal(a.hashvalues, b.hashvalues)
+
+
+def test_similar_texts_share_most_hashvalues():
+    a = _minhash_for("authentication manager")
+    b = _minhash_for("authentication managers")
+    overlap = np.sum(a.hashvalues == b.hashvalues) / len(a.hashvalues)
+    assert overlap > 0.5
+
+
+def test_unrelated_texts_share_few_hashvalues():
+    a = _minhash_for("authentication manager")
+    b = _minhash_for("file system watcher")
+    overlap = np.sum(a.hashvalues == b.hashvalues) / len(a.hashvalues)
+    assert overlap < 0.3
+
+
+def test_update_mutates_hashvalues():
+    m = MinHash(num_perm=64)
+    before = m.hashvalues.copy()
+    m.update(b"hello")
+    assert not np.array_equal(m.hashvalues, before)
+
+
+# ── MinHashLSH ────────────────────────────────────────────────────────────────
+
+def test_near_duplicates_are_candidates():
+    lsh = MinHashLSH(threshold=0.5, num_perm=128)
+    a = _minhash_for("authentication manager")
+    b = _minhash_for("authentication managers")
+    lsh.insert("a", a)
+    lsh.insert("b", b)
+    assert "b" in lsh.query(a)
+
+
+def test_unrelated_strings_not_candidates():
+    lsh = MinHashLSH(threshold=0.5, num_perm=128)
+    a = _minhash_for("authentication manager")
+    b = _minhash_for("file system watcher")
+    lsh.insert("a", a)
+    lsh.insert("b", b)
+    assert "b" not in lsh.query(a)
+
+
+def test_query_always_returns_self():
+    lsh = MinHashLSH(threshold=0.5, num_perm=128)
+    m = _minhash_for("graphextractor")
+    lsh.insert("x", m)
+    assert "x" in lsh.query(m)
+
+
+def test_duplicate_insert_raises():
+    lsh = MinHashLSH(threshold=0.5, num_perm=128)
+    m = _minhash_for("foo")
+    lsh.insert("key", m)
+    with pytest.raises(ValueError, match="already exists"):
+        lsh.insert("key", m)
+
+
+# ── _optimal_lsh_params ───────────────────────────────────────────────────────
+
+def test_optimal_params_within_budget():
+    b, r = _optimal_lsh_params(0.5, 128)
+    assert b >= 1 and r >= 1
+    assert b * r <= 128
+
+
+def test_optimal_params_cached():
+    result1 = _optimal_lsh_params(0.7, 128)
+    result2 = _optimal_lsh_params(0.7, 128)
+    assert result1 is result2
+
+
+# ── EDR regression: scipy / numpy.testing must not be imported ──────────────────
+
+def test_dedup_import_does_not_pull_scipy_or_numpy_testing():
+    import sys
+    for mod in ("scipy", "numpy.testing"):
+        sys.modules.pop(mod, None)
+    import graphify.dedup  # noqa: F401
+    assert "scipy" not in sys.modules
+    assert "numpy.testing" not in sys.modules