Add defensible orphaned audio detection

tests/test_health.py

@@ -2,6 +2,7 @@ from pathlib import Path
 
 from serato_doctor.health import analyze_health
 from serato_doctor.models.crate import Crate, CrateKind
+from serato_doctor.models.database import DatabaseTrack, SeratoDatabase
 from serato_doctor.models.filesystem import BrokenSymlink
 from serato_doctor.models.library import Library
 from serato_doctor.models.reference import TrackReference
@@ -49,6 +50,7 @@ def test_health_report_exposes_each_metric():
     assert report.duplicate_filename_groups == 1
     assert report.duplicate_files == 1
     assert report.unused_tracks == 3
+    assert report.orphan_candidates is None
     assert report.suggested_matches == 1
 
 
@@ -60,6 +62,32 @@ def test_empty_library_has_no_health_score():
     assert report.scored_references == 0
     assert not report.database_present
     assert report.tracks_missing_from_database == 0
+    assert report.orphan_candidates is None
+
+
+def test_orphan_candidates_exclude_tracks_known_to_serato_or_crates():
+    tracks = [
+        track("Crated.mp3"),
+        track("LibraryOnly.mp3"),
+        track("OutsideEverything.mp3"),
+    ]
+    database = SeratoDatabase(
+        Path("database V2"),
+        "test",
+        (
+            DatabaseTrack(
+                Path("/new/House/LibraryOnly.mp3"), "LibraryOnly.mp3"
+            ),
+        ),
+    )
+    library = Library.build(
+        [reference("Crated.mp3")], tracks, database=database
+    )
+
+    report = analyze_health(library)
+
+    assert report.unused_tracks == 2
+    assert report.orphan_candidates == 1
 
 
 def test_smart_crate_references_are_reported_but_not_scored():