Fix filename: omit empty artist suffix, sanitize single quotes

Regular (non-compilation) tracks had an empty artist producing
trailing '_-_.flac'. Now artist suffix is only appended when non-empty.
Also added single quote to _sanitize_name's removed characters.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/musiksammlung/ripper.py

@@ -63,7 +63,7 @@ def _sanitize_name(name: str) -> str:
         Cleaned name (spaces -> underscores)
     """
     name = name.replace(" ", "_")
-    name = re.sub(r'[<>:"/\\|?*]', "", name)
+    name = re.sub(r'[<>:"\'/\\|?*]', "", name)
     name = name.strip("_")
     return name
 
@@ -323,10 +323,14 @@ def _rename_files(
         num = int(m.group(1))
         track = by_num.get(num)
         if track:
-            new_name = (
-                f"{num:02d}_-_{_sanitize_name(track.title)}_-_"
-                f"{_sanitize_name(track.artist)}{audio_format.extension}"
-            )
+            safe_title = _sanitize_name(track.title)
+            if track.artist:
+                new_name = (
+                    f"{num:02d}_-_{safe_title}_-_"
+                    f"{_sanitize_name(track.artist)}{audio_format.extension}"
+                )
+            else:
+                new_name = f"{num:02d}_-_{safe_title}{audio_format.extension}"
         else:
             new_name = f"{num:02d}{audio_format.extension}"
 

tests/test_ripper.py

@@ -28,6 +28,7 @@ class TestSanitizeName:
         assert _sanitize_name("Test/Track:Name") == "TestTrackName"
         assert _sanitize_name('Test<Track>"Name') == "TestTrackName"
         assert _sanitize_name("Test|Track?Name*") == "TestTrackName"
+        assert _sanitize_name("It's_a_Test") == "Its_a_Test"
 
     def test_keep_umlauts(self) -> None:
         assert _sanitize_name("Grüße aus Österreich") == "Grüße_aus_Österreich"
@@ -282,6 +283,13 @@ class TestRenameFiles:
         _rename_files(tmp_path, tracks, AudioFormat.FLAC)
         assert (tmp_path / "01_-_My_Title_-_Art_ist.flac").exists()
 
+    def test_regular_track_without_artist(self, tmp_path: Path) -> None:
+        """Reguläre Tracks (artist='') → kein '_-_Artist'-Suffix."""
+        (tmp_path / "track01.flac").touch()
+        tracks = [TrackInfo(1, "", "Allegro con brio")]
+        _rename_files(tmp_path, tracks, AudioFormat.FLAC)
+        assert (tmp_path / "01_-_Allegro_con_brio.flac").exists()
+
 
 # ---------------------------------------------------------------------------
 # interactive_rip – EAN/Barcode-Integration