dedup: modulo audio fingerprinting via fpcalc + cache SQLite

Nuovo modulo core.dedup per rilevare brani audio duplicati usando
Chromaprint (fpcalc): scan cartella (opzionalmente ricorsivo),
fingerprint acustico via fpcalc -json, cache SQLite in
_get_config_dir()/dedup_cache.db per non ricalcolare al re-scan,
raggruppamento per fingerprint identico + ordering per bitrate DESC.
move_to_trash() usa send2trash (reversibile via Finder/Explorer).

- core/paths.py: find_fpcalc() con fallback dev su project bundle_bin
- core/dedup.py: scan_folder, compute_fingerprint, move_to_trash
- tests/test_dedup.py: 9 unit test (mock fpcalc + send2trash)
- requirements.txt: send2trash>=1.8.0
- build_macos.py: download fpcalc universal binary da GitHub releases
- build_windows.py: download fpcalc.exe da GitHub releases

tests/test_dedup.py

@@ -0,0 +1,190 @@
+"""Test per core.dedup — audio fingerprinting via fpcalc + cache SQLite.
+
+Tutti gli unit test usano mock per fpcalc / send2trash: nessuna
+integrazione reale, nessun file audio necessario.
+"""
+
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+from unittest import mock
+
+import pytest
+
+from core import dedup
+
+
+# ------------------------------------------------------------------
+# Fixture: dedup con cache DB isolato in tmp_path
+# ------------------------------------------------------------------
+@pytest.fixture
+def patched_cache(tmp_path, monkeypatch):
+    """Isola la cache SQLite in tmp_path per non toccare il config dir."""
+    db = tmp_path / "dedup_cache_test.db"
+    monkeypatch.setattr(dedup, "_cache_db_path", lambda: db)
+    return db
+
+
+def _make_fake_audio(tmp_path: Path, name: str, size: int = 1024) -> Path:
+    """Crea un file 'audio' fake (byte casuali con estensione .mp3)."""
+    f = tmp_path / name
+    f.write_bytes(b"\x00" * size)
+    return f
+
+
+# ------------------------------------------------------------------
+# scan_folder
+# ------------------------------------------------------------------
+class TestScanFolder:
+    def test_no_audio_files(self, tmp_path, patched_cache):
+        """Cartella senza audio -> gruppi vuoti, nessuna eccezione."""
+        # Solo un file .txt (non audio)
+        (tmp_path / "readme.txt").write_text("hello")
+
+        # Anche senza fpcalc disponibile, con 0 audio file ritorna [].
+        with mock.patch.object(dedup, "find_fpcalc", return_value="/fake/fpcalc"):
+            groups = dedup.scan_folder(str(tmp_path), recursive=False)
+
+        assert groups == []
+
+    def test_uses_cache_on_second_scan(self, tmp_path, patched_cache):
+        """Prima scan chiama fpcalc; seconda scan riusa la cache."""
+        _make_fake_audio(tmp_path, "song.mp3", size=2048)
+
+        calls: list[str] = []
+
+        def fake_compute(fpcalc, path):
+            calls.append(path)
+            return {"duration": 180.5, "fingerprint": "FP-A"}
+
+        with mock.patch.object(dedup, "find_fpcalc", return_value="/fake/fpcalc"), \
+             mock.patch.object(dedup, "compute_fingerprint", side_effect=fake_compute), \
+             mock.patch.object(dedup, "get_bitrate", return_value=320):
+            # Prima invocazione: fpcalc DEVE essere chiamato
+            groups1 = dedup.scan_folder(str(tmp_path), recursive=False)
+            first_calls = len(calls)
+
+            # Seconda invocazione (stesso file, stesso mtime/size):
+            # cache HIT, fpcalc NON viene richiamato
+            groups2 = dedup.scan_folder(str(tmp_path), recursive=False)
+            second_calls = len(calls)
+
+        assert first_calls == 1, "prima scan deve chiamare fpcalc una volta"
+        assert second_calls == 1, "seconda scan deve riusare la cache"
+        # Con un solo file, nessun gruppo di duplicati
+        assert groups1 == []
+        assert groups2 == []
+
+    def test_groups_duplicates(self, tmp_path, patched_cache):
+        """3 file con lo stesso fingerprint -> 1 gruppo di 3, ordinato per bitrate DESC."""
+        _make_fake_audio(tmp_path, "a.mp3", size=1000)
+        _make_fake_audio(tmp_path, "b.mp3", size=3000)  # size maggiore
+        _make_fake_audio(tmp_path, "c.mp3", size=2000)
+
+        # Tutti stesso fingerprint. Bitrate differente per verificare
+        # l'ordinamento: b=320 (top), a=192, c=128.
+        bitrate_by_name = {"a.mp3": 192, "b.mp3": 320, "c.mp3": 128}
+
+        with mock.patch.object(dedup, "find_fpcalc", return_value="/fake/fpcalc"), \
+             mock.patch.object(dedup, "compute_fingerprint",
+                               return_value={"duration": 200, "fingerprint": "SAME-FP"}), \
+             mock.patch.object(dedup, "get_bitrate",
+                               side_effect=lambda p: bitrate_by_name[Path(p).name]):
+            groups = dedup.scan_folder(str(tmp_path), recursive=False)
+
+        assert len(groups) == 1, "esattamente un gruppo di duplicati"
+        g = groups[0]
+        assert len(g) == 3, "tre file nel gruppo"
+        # Ordine: bitrate DESC -> b (320), a (192), c (128)
+        assert [Path(e["path"]).name for e in g] == ["b.mp3", "a.mp3", "c.mp3"]
+        # Ogni entry ha i campi attesi
+        for e in g:
+            assert set(e.keys()) >= {"path", "size", "bitrate", "duration", "fingerprint"}
+            assert e["fingerprint"] == "SAME-FP"
+
+    def test_ignores_singletons(self, tmp_path, patched_cache):
+        """File con fingerprint unico non compaiono nei gruppi."""
+        _make_fake_audio(tmp_path, "dup1.mp3")
+        _make_fake_audio(tmp_path, "dup2.mp3")
+        _make_fake_audio(tmp_path, "unique.mp3")
+
+        fp_by_name = {"dup1.mp3": "FP-X", "dup2.mp3": "FP-X", "unique.mp3": "FP-Y"}
+
+        def fake_compute(fpcalc, path):
+            return {"duration": 100, "fingerprint": fp_by_name[Path(path).name]}
+
+        with mock.patch.object(dedup, "find_fpcalc", return_value="/fake/fpcalc"), \
+             mock.patch.object(dedup, "compute_fingerprint", side_effect=fake_compute), \
+             mock.patch.object(dedup, "get_bitrate", return_value=256):
+            groups = dedup.scan_folder(str(tmp_path), recursive=False)
+
+        # Solo il gruppo con dup1/dup2
+        assert len(groups) == 1
+        names = {Path(e["path"]).name for e in groups[0]}
+        assert names == {"dup1.mp3", "dup2.mp3"}
+        # unique.mp3 non appare in nessun gruppo
+        for g in groups:
+            for e in g:
+                assert Path(e["path"]).name != "unique.mp3"
+
+
+# ------------------------------------------------------------------
+# move_to_trash
+# ------------------------------------------------------------------
+class TestMoveToTrash:
+    def test_returns_moved_and_failed_summary(self, tmp_path, patched_cache):
+        """Verifica che il summary contenga moved/failed correttamente."""
+        # 2 path OK + 1 path che alza eccezione
+        ok1 = str(tmp_path / "ok1.mp3")
+        ok2 = str(tmp_path / "ok2.mp3")
+        bad = str(tmp_path / "bad.mp3")
+
+        def fake_send(p):
+            if p == bad:
+                raise OSError("simulated failure")
+            # ok: no-op
+
+        # Il modulo importa send2trash *dentro* la funzione, quindi
+        # dobbiamo patchare il modulo importato.
+        with mock.patch("send2trash.send2trash", side_effect=fake_send):
+            res = dedup.move_to_trash([ok1, bad, ok2])
+
+        assert set(res["moved"]) == {ok1, ok2}
+        assert len(res["failed"]) == 1
+        assert res["failed"][0]["path"] == bad
+        assert "simulated failure" in res["failed"][0]["error"]
+
+
+# ------------------------------------------------------------------
+# compute_fingerprint
+# ------------------------------------------------------------------
+class TestComputeFingerprint:
+    def test_timeout_returns_none(self):
+        """Timeout di fpcalc -> None (non alza eccezione)."""
+        with mock.patch("core.dedup.subprocess.run",
+                        side_effect=subprocess.TimeoutExpired(cmd="fpcalc", timeout=30)):
+            result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
+        assert result is None
+
+    def test_success_returns_dict(self):
+        """Output JSON valido -> {duration, fingerprint}."""
+        fake_proc = mock.Mock()
+        fake_proc.returncode = 0
+        fake_proc.stdout = '{"duration": 123.4, "fingerprint": "ABCDEF"}'
+        with mock.patch("core.dedup.subprocess.run", return_value=fake_proc):
+            result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
+        assert result == {"duration": 123.4, "fingerprint": "ABCDEF"}
+
+    def test_bad_json_returns_none(self):
+        fake_proc = mock.Mock()
+        fake_proc.returncode = 0
+        fake_proc.stdout = "not json at all"
+        with mock.patch("core.dedup.subprocess.run", return_value=fake_proc):
+            result = dedup.compute_fingerprint("/fake/fpcalc", "/some/file.mp3")
+        assert result is None
+
+    def test_missing_fpcalc_returns_none(self):
+        # Nessuna chiamata subprocess se fpcalc e' vuoto
+        result = dedup.compute_fingerprint("", "/some/file.mp3")
+        assert result is None