feat: add Track model with GRDB record conformance and tests

Introduces the core Track struct (nonisolated to work with project-wide
MainActor default isolation), its FetchableRecord/MutablePersistableRecord
conformances, a DEBUG fixture helper, and three Swift Testing tests covering
round-trip persistence, ID assignment on insert, and deterministic hash computation.

Music.xcodeproj/project.pbxproj

@@ -38,10 +38,10 @@
 		C46B2CC32FC2449900F95A24 /* Exceptions for "Music" folder in "Music" target */ = {
 			isa = PBXFileSystemSynchronizedBuildFileExceptionSet;
 			membershipExceptions = (
-				"Models/.gitkeep",
-				"Services/.gitkeep",
-				"ViewModels/.gitkeep",
-				"Views/.gitkeep",
+				Models/.gitkeep,
+				Services/.gitkeep,
+				ViewModels/.gitkeep,
+				Views/.gitkeep,
 			);
 			target = C46B2C8C2FC2448700F95A24 /* Music */;
 		};

Music/Models/Track.swift

@@ -0,0 +1,88 @@
+import Foundation
+import GRDB
+
+// `nonisolated` opts this struct out of the project-wide `default-isolation = MainActor`
+// setting. Without it, the compiler tries to infer MainActor isolation and hits a circular
+// reference when synthesising Equatable/Hashable conformances.
+nonisolated struct Track: Codable, Identifiable, Equatable, Hashable, Sendable {
+    var id: Int64?
+    var fileURL: String
+    var title: String
+    var artist: String
+    var albumArtist: String
+    var album: String
+    var genre: String
+    var year: Int?
+    var trackNumber: Int?
+    var discNumber: Int?
+    var duration: Double
+    var bpm: Int?
+    var composer: String
+    var fileFormat: String
+    var bitrate: Int?
+    var sampleRate: Int?
+    var fileSize: Int64
+    var artworkData: Data?
+    var playCount: Int
+    var lastPlayedAt: Date?
+    var rating: Int
+    var dateAdded: Date
+    var dateModified: Date
+    var fileHash: String
+
+    static func computeHash(fileSize: Int64, modificationDate: Date) -> String {
+        "\(fileSize)_\(Int(modificationDate.timeIntervalSince1970))"
+    }
+}
+
+// Also `nonisolated` so the GRDB protocol conformances (FetchableRecord,
+// MutablePersistableRecord) are not inferred as MainActor-isolated, which
+// would prevent using them in Sendable contexts.
+nonisolated extension Track: FetchableRecord, MutablePersistableRecord {
+    static let databaseTableName = "tracks"
+
+    mutating func didInsert(_ inserted: InsertionSuccess) {
+        id = inserted.rowID
+    }
+}
+
+#if DEBUG
+extension Track {
+    static func fixture(
+        id: Int64? = nil,
+        fileURL: String = "/tmp/test.mp3",
+        title: String = "Test Song",
+        artist: String = "Test Artist",
+        albumArtist: String = "Test Artist",
+        album: String = "Test Album",
+        genre: String = "Rock",
+        year: Int? = 2024,
+        trackNumber: Int? = 1,
+        discNumber: Int? = 1,
+        duration: Double = 210.0,
+        bpm: Int? = 120,
+        composer: String = "Test Composer",
+        fileFormat: String = "mp3",
+        bitrate: Int? = 320,
+        sampleRate: Int? = 44100,
+        fileSize: Int64 = 5_000_000,
+        artworkData: Data? = nil,
+        playCount: Int = 0,
+        lastPlayedAt: Date? = nil,
+        rating: Int = 0,
+        dateAdded: Date = Date(),
+        dateModified: Date = Date(),
+        fileHash: String = "5000000_1700000000"
+    ) -> Track {
+        Track(
+            id: id, fileURL: fileURL, title: title, artist: artist,
+            albumArtist: albumArtist, album: album, genre: genre, year: year,
+            trackNumber: trackNumber, discNumber: discNumber, duration: duration,
+            bpm: bpm, composer: composer, fileFormat: fileFormat, bitrate: bitrate,
+            sampleRate: sampleRate, fileSize: fileSize, artworkData: artworkData,
+            playCount: playCount, lastPlayedAt: lastPlayedAt, rating: rating,
+            dateAdded: dateAdded, dateModified: dateModified, fileHash: fileHash
+        )
+    }
+}
+#endif

MusicTests/MusicTests.swift

@@ -1,17 +0,0 @@
-//
-//  MusicTests.swift
-//  MusicTests
-//
-//  Created by Laurent Morvillier on 23/05/2026.
-//
-
-import Testing
-@testable import Music
-
-struct MusicTests {
-
-    @Test func example() async throws {
-        // Write your test here and use APIs like `#expect(...)` to check expected conditions.
-    }
-
-}

MusicTests/TrackTests.swift

@@ -0,0 +1,81 @@
+import Foundation
+import Testing
+import GRDB
+@testable import Music
+
+struct TrackTests {
+    // Creates a fresh in-memory database with the tracks table schema.
+    // Each test gets its own isolated DatabaseQueue so tests don't share state.
+    private static func makeDB() throws -> DatabaseQueue {
+        let dbQueue = try DatabaseQueue()
+        try dbQueue.write { db in
+            try db.create(table: "tracks") { t in
+                t.autoIncrementedPrimaryKey("id")
+                t.column("fileURL", .text).notNull().unique()
+                t.column("title", .text).notNull()
+                t.column("artist", .text).notNull()
+                t.column("albumArtist", .text).notNull()
+                t.column("album", .text).notNull()
+                t.column("genre", .text).notNull()
+                t.column("year", .integer)
+                t.column("trackNumber", .integer)
+                t.column("discNumber", .integer)
+                t.column("duration", .double).notNull()
+                t.column("bpm", .integer)
+                t.column("composer", .text).notNull()
+                t.column("fileFormat", .text).notNull()
+                t.column("bitrate", .integer)
+                t.column("sampleRate", .integer)
+                t.column("fileSize", .integer).notNull()
+                t.column("artworkData", .blob)
+                t.column("playCount", .integer).notNull().defaults(to: 0)
+                t.column("lastPlayedAt", .datetime)
+                t.column("rating", .integer).notNull().defaults(to: 0)
+                t.column("dateAdded", .datetime).notNull()
+                t.column("dateModified", .datetime).notNull()
+                t.column("fileHash", .text).notNull()
+            }
+        }
+        return dbQueue
+    }
+
+    // Verifies that Track can round-trip through GRDB's encoding/decoding,
+    // meaning it correctly conforms to FetchableRecord and PersistableRecord.
+    @Test func roundTripThroughDatabase() throws {
+        let dbQueue = try TrackTests.makeDB()
+        try dbQueue.write { db in
+            var track = Track.fixture(title: "Bohemian Rhapsody", artist: "Queen")
+            try track.insert(db)
+
+            #expect(track.id != nil)
+
+            let fetched = try Track.fetchOne(db, key: track.id)
+            #expect(fetched?.title == "Bohemian Rhapsody")
+            #expect(fetched?.artist == "Queen")
+            #expect(fetched?.duration == 210.0)
+        }
+    }
+
+    // Verifies that didInsert assigns the auto-incremented ID after insertion.
+    @Test func didInsertAssignsId() throws {
+        let dbQueue = try TrackTests.makeDB()
+        try dbQueue.write { db in
+            var track = Track.fixture()
+            #expect(track.id == nil)
+            try track.insert(db)
+            #expect(track.id != nil)
+        }
+    }
+
+    // Verifies the fileHash computation produces a deterministic string from size + date.
+    @Test func computeHashIsDeterministic() {
+        let date = Date(timeIntervalSince1970: 1700000000)
+        let hash1 = Track.computeHash(fileSize: 5_000_000, modificationDate: date)
+        let hash2 = Track.computeHash(fileSize: 5_000_000, modificationDate: date)
+        #expect(hash1 == hash2)
+        #expect(hash1 == "5000000_1700000000")
+
+        let different = Track.computeHash(fileSize: 999, modificationDate: date)
+        #expect(different != hash1)
+    }
+}