Import existing LinTunes project

Snapshot of the existing codebase before working through the TASKS.md
backlog. Real library data (data/) and the iTunes import fixture
(itunes-test-library/) are gitignored.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tagging.py

@@ -0,0 +1,60 @@
+import pytest
+
+from lintunes import tagging
+
+
+FIELDS = {
+    "name": "Test Title",
+    "artist": "Test Artist",
+    "album_artist": "Test Album Artist",
+    "album": "Test Album",
+    "genre": "Electronic",
+    "composer": "Test Composer",
+    "comments": "A comment",
+    "grouping": "Test Group",
+    "year": 2021,
+    "track_number": 3,
+    "track_count": 12,
+    "disc_number": 1,
+    "disc_count": 2,
+    "compilation": True,
+    "bpm": 120,
+}
+
+
+@pytest.mark.parametrize("fixture", ["mp3_file", "m4a_file", "flac_file"])
+def test_write_read_round_trip(fixture, request):
+    path = request.getfixturevalue(fixture)
+    tagging.write_tags(path, FIELDS)
+    read = tagging.read_tags(path)
+
+    for key in ("name", "artist", "album_artist", "album", "genre",
+                "composer", "comments"):
+        assert read.get(key) == FIELDS[key], key
+    assert read.get("year") == 2021
+    assert read.get("track_number") == 3
+    assert read.get("track_count") == 12
+    assert read.get("disc_number") == 1
+    assert read.get("total_time", 0) > 500  # ~1s of audio
+    assert read.get("size", 0) > 0
+
+
+def test_read_tags_reports_audio_properties(mp3_file):
+    read = tagging.read_tags(mp3_file)
+    assert read.get("kind") == "MPEG audio file"
+    assert read.get("sample_rate", 0) > 0
+
+
+def test_no_artwork_in_generated_file(mp3_file):
+    assert tagging.read_embedded_artwork(mp3_file) is None
+
+
+@pytest.mark.parametrize("fixture", ["mp3_file", "m4a_file", "flac_file"])
+def test_artwork_write_read_round_trip(fixture, request, jpeg_bytes):
+    path = request.getfixturevalue(fixture)
+    assert tagging.read_embedded_artwork(path) is None
+    tagging.write_artwork(path, jpeg_bytes, "image/jpeg")
+    assert tagging.read_embedded_artwork(path) == jpeg_bytes
+    # Replacing art works too (no duplicate covers accumulate)
+    tagging.write_artwork(path, jpeg_bytes + b"\x00", "image/jpeg")
+    assert tagging.read_embedded_artwork(path) == jpeg_bytes + b"\x00"