test: add deezer crypto and filename tests

internal/deezer/blowfish_test.go

@@ -0,0 +1,56 @@
+package deezer
+
+import (
+	"bytes"
+	"crypto/cipher"
+	"encoding/hex"
+	"testing"
+
+	"golang.org/x/crypto/blowfish"
+)
+
+func TestBlowfishKey(t *testing.T) {
+	tests := []struct {
+		trackID string
+		want    string
+	}{
+		{"3135556", "6c6c666b39662c37652575603c643439"},
+		{"123456789", "6d34656061377f31322a7336393f626b"},
+		{"1", "3464656e343a7d3a672c236a33696061"},
+	}
+
+	for _, tt := range tests {
+		got := hex.EncodeToString(BlowfishKey(tt.trackID))
+		if got != tt.want {
+			t.Errorf("BlowfishKey(%q) = %s, want %s", tt.trackID, got, tt.want)
+		}
+	}
+}
+
+func TestDecryptBlowfishRoundTrip(t *testing.T) {
+	key := BlowfishKey("3135556")
+	plaintext := bytes.Repeat([]byte("01234567"), 16)
+
+	block, err := blowfish.NewCipher(key)
+	if err != nil {
+		t.Fatalf("NewCipher: %v", err)
+	}
+
+	encrypted := make([]byte, len(plaintext))
+	cipher.NewCBCEncrypter(block, blowfishIV).CryptBlocks(encrypted, plaintext)
+
+	decrypted, err := DecryptBlowfish(encrypted, key)
+	if err != nil {
+		t.Fatalf("DecryptBlowfish: %v", err)
+	}
+
+	if !bytes.Equal(decrypted, plaintext) {
+		t.Errorf("round trip mismatch: got %x, want %x", decrypted, plaintext)
+	}
+}
+
+func TestDecryptBlowfishInvalidKey(t *testing.T) {
+	if _, err := DecryptBlowfish(make([]byte, 8), nil); err == nil {
+		t.Error("expected error for empty key")
+	}
+}

internal/deezer/ecb_test.go

@@ -0,0 +1,72 @@
+package deezer
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestZeroPad(t *testing.T) {
+	tests := []struct {
+		length int
+		want   int
+	}{
+		{0, 0},
+		{1, 16},
+		{15, 16},
+		{16, 16},
+		{17, 32},
+	}
+
+	for _, tt := range tests {
+		padded := zeroPad(make([]byte, tt.length))
+		if len(padded) != tt.want {
+			t.Errorf("zeroPad(len %d) = len %d, want %d", tt.length, len(padded), tt.want)
+		}
+	}
+}
+
+func TestZeroPadPreservesData(t *testing.T) {
+	data := []byte("secret")
+	padded := zeroPad(data)
+
+	if !bytes.Equal(padded[:len(data)], data) {
+		t.Errorf("zeroPad changed data: got %q", padded[:len(data)])
+	}
+	for _, b := range padded[len(data):] {
+		if b != 0 {
+			t.Errorf("padding is not zero: %v", padded)
+		}
+	}
+}
+
+func TestECBRoundTrip(t *testing.T) {
+	key := []byte("0123456789abcdef")
+	plaintext := zeroPad([]byte("some secret data"))
+
+	encrypted, err := ecbEncrypt(key, plaintext)
+	if err != nil {
+		t.Fatalf("ecbEncrypt: %v", err)
+	}
+	if bytes.Equal(encrypted, plaintext) {
+		t.Fatal("encrypted data equals plaintext")
+	}
+
+	decrypted, err := ecbDecrypt(key, encrypted)
+	if err != nil {
+		t.Fatalf("ecbDecrypt: %v", err)
+	}
+	if !bytes.Equal(decrypted, plaintext) {
+		t.Errorf("round trip mismatch: got %q, want %q", decrypted, plaintext)
+	}
+}
+
+func TestECBRejectsPartialBlock(t *testing.T) {
+	key := []byte("0123456789abcdef")
+
+	if _, err := ecbEncrypt(key, make([]byte, 15)); err == nil {
+		t.Error("expected error for data not a multiple of the block size")
+	}
+	if _, err := ecbDecrypt(key, make([]byte, 17)); err == nil {
+		t.Error("expected error for data not a multiple of the block size")
+	}
+}

internal/deezer/track_test.go

@@ -0,0 +1,109 @@
+package deezer
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+func TestFullTitle(t *testing.T) {
+	tests := []struct {
+		title   string
+		version string
+		want    string
+	}{
+		{"Song", "", "Song"},
+		{"Song", "(Remix)", "Song (Remix)"},
+	}
+
+	for _, tt := range tests {
+		track := &Track{Title: tt.title, Version: tt.version}
+		if got := track.FullTitle(); got != tt.want {
+			t.Errorf("FullTitle() = %q, want %q", got, tt.want)
+		}
+	}
+}
+
+func TestFilename(t *testing.T) {
+	tests := []struct {
+		name        string
+		track       Track
+		kind        Kind
+		mediaFormat string
+		want        string
+	}{
+		{
+			name:        "album with numeric track number",
+			track:       Track{Artist: "Artist", Title: "Song", TrackNumber: "1"},
+			kind:        KindAlbum,
+			mediaFormat: "MP3_320",
+			want:        "01. Artist - Song.mp3",
+		},
+		{
+			name:        "album with non-numeric track number",
+			track:       Track{Artist: "Artist", Title: "Song", TrackNumber: "A"},
+			kind:        KindAlbum,
+			mediaFormat: "MP3_320",
+			want:        "A. Artist - Song.mp3",
+		},
+		{
+			name:        "playlist has no prefix",
+			track:       Track{Artist: "Artist", Title: "Song", TrackNumber: "1"},
+			kind:        KindPlaylist,
+			mediaFormat: "MP3_128",
+			want:        "Artist - Song.mp3",
+		},
+		{
+			name:        "flac extension",
+			track:       Track{Artist: "Artist", Title: "Song"},
+			kind:        KindTrack,
+			mediaFormat: "FLAC",
+			want:        "Artist - Song.flac",
+		},
+		{
+			name:        "version appended",
+			track:       Track{Artist: "Artist", Title: "Song", Version: "(Live)"},
+			kind:        KindTrack,
+			mediaFormat: "MP3_320",
+			want:        "Artist - Song (Live).mp3",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.track.Filename(tt.kind, tt.mediaFormat); got != tt.want {
+				t.Errorf("Filename() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFilenameSanitizesSeparators(t *testing.T) {
+	track := Track{Artist: "AC/DC", Title: "Song"}
+	got := track.Filename(KindTrack, "MP3_320")
+
+	if strings.ContainsRune(got, '/') {
+		t.Errorf("Filename() contains a path separator: %q", got)
+	}
+	if !strings.HasSuffix(got, ".mp3") {
+		t.Errorf("Filename() = %q, want .mp3 suffix", got)
+	}
+}
+
+func TestContributorsUnmarshalJSON(t *testing.T) {
+	var c Contributors
+	if err := json.Unmarshal([]byte("[]"), &c); err != nil {
+		t.Fatalf("unmarshal empty array: %v", err)
+	}
+	if len(c.MainArtists) != 0 || len(c.Composers) != 0 || len(c.Authors) != 0 {
+		t.Errorf("expected empty contributors, got %+v", c)
+	}
+
+	data := `{"main_artist":["A","B"],"composer":["C"],"author":["D"]}`
+	if err := json.Unmarshal([]byte(data), &c); err != nil {
+		t.Fatalf("unmarshal object: %v", err)
+	}
+	if len(c.MainArtists) != 2 || c.MainArtists[0] != "A" || len(c.Composers) != 1 || len(c.Authors) != 1 {
+		t.Errorf("unexpected contributors: %+v", c)
+	}
+}