Add duplicate filename diagnostics

tests/test_duplicates.py

@@ -0,0 +1,57 @@
+from pathlib import Path
+
+from serato_doctor.duplicates import find_duplicate_groups
+from serato_doctor.models.duplicate import DuplicateKind
+from serato_doctor.models.track import DiskTrack
+
+
+def track(path):
+    path = Path(path)
+    return DiskTrack(path, path.name, 100, path.suffix.lower())
+
+
+def test_exact_names_in_different_folders_form_a_group():
+    groups = find_duplicate_groups(
+        [track("/A/Song.mp3"), track("/B/Song.mp3")]
+    )
+
+    assert len(groups) == 1
+    assert groups[0].kind is DuplicateKind.EXACT_NAME
+    assert groups[0].display_name == "Song.mp3"
+    assert groups[0].extra_files == 1
+
+
+def test_case_only_difference_is_an_exact_name_duplicate():
+    groups = find_duplicate_groups(
+        [track("/A/SONG.MP3"), track("/B/song.mp3")]
+    )
+
+    assert groups[0].kind is DuplicateKind.EXACT_NAME
+
+
+def test_numeric_suffixes_form_a_suspected_cloud_conflict_group():
+    groups = find_duplicate_groups(
+        [
+            track("/A/Track.mp3"),
+            track("/B/Track 2.mp3"),
+            track("/C/Track 3.mp3"),
+        ]
+    )
+
+    assert len(groups) == 1
+    assert groups[0].kind is DuplicateKind.CLOUD_CONFLICT
+    assert groups[0].display_name == "Track.mp3"
+    assert groups[0].extra_files == 2
+    assert [item.path for item in groups[0].tracks] == [
+        Path("/A/Track.mp3"),
+        Path("/B/Track 2.mp3"),
+        Path("/C/Track 3.mp3"),
+    ]
+
+
+def test_unrelated_and_single_files_are_not_reported():
+    groups = find_duplicate_groups(
+        [track("/A/First.mp3"), track("/B/Second.mp3")]
+    )
+
+    assert groups == ()