feat(audio): T-0.3 spike lolos — engine oto v3.5.1 async + fallback anggun (F-024 awal)

Makefile

@@ -3,7 +3,7 @@ BINARY := tia-love
 .PHONY: build run test vet fmt clean
 
 build:
-	go build -o $(BINARY) ./cmd/tia-love
+	CGO_ENABLED=0 go build -o $(BINARY) ./cmd/tia-love
 
 run: build
 	./$(BINARY)

THIRD_PARTY_NOTICES.md

@@ -20,6 +20,9 @@ Repo referensi hanya ada di `reference/` (git-ignored).
 |---|---|---|
 | bubbletea | v2.1.0 | MIT |
 | lipgloss | v2.0.6 | MIT |
+| oto | v3.5.1 | Apache-2.0 |
+| purego *(transitif oto — driver ALSA)* | v0.11.0 | Apache-2.0 |
+| jfreymuth/pulse *(transitif oto — driver PulseAudio pure-Go)* | v0.1.3 | MIT |
 
 *(Daftar bertambah setiap dependency baru diadopsi; wajib selaras dengan kebijakan aset PRD Appendix C.)*
 

docs/ASSETS.md

@@ -7,7 +7,8 @@ tersedia atribusinya dari menu **Tentang** di aplikasi.
 | Aset | Sumber | Lisensi | Tanggal | Status | File target |
 |---|---|---|---|---|---|
 | Palet Catppuccin (Mocha/Latte) | https://github.com/catppuccin/catppuccin | MIT | — | planned (Phase 1) | `internal/ui/theme/catppuccin.go` |
-| Efek suara UI (click, modal, notif, error) | Kenney Interface Sounds — https://kenney.nl/assets/interface-sounds | CC0 1.0 | — | pending (T-0.6) | `internal/audio/assets/*.wav` |
+| Efek suara UI — placeholder (8 WAV, generated) | buatan sendiri (script sinus, no external) | ikut lisensi tia | 2026-10-15 | dipakai sementara (T-0.3) | `internal/audio/assets/*.wav` |
+| Efek suara UI final (click, modal, notif, error) | Kenney Interface Sounds — https://kenney.nl/assets/interface-sounds | CC0 1.0 | — | pending (T-0.6) | `internal/audio/assets/*.wav` |
 | Logo ASCII `tia` | buatan sendiri | ikut lisensi tia | 2026-10 | planned (Phase 1) | `internal/ui/animation/logo.go` |
 | Ikon/glyph | Unicode standar (●, ○, ▶, ⟳, ✔, ⚠, ✕) | bebas | 2026-10 | dipakai | di kode UI |
 

docs/spikes/T-0.3-audio.md

@@ -0,0 +1,59 @@
+# Spike T-0.3 — Audio (oto v3.5.1, CGO_ENABLED=0)
+
+> Status: ✅ **LOLOS** · Tanggal: 2026-10-15 · Mesin: Linux (PipeWire + pipewire-pulse aktif, `/dev/snd` tersedia)
+
+## Tujuan (PRD Phase 0)
+
+Buktikan: suara bisa diputar dari binary `CGO_ENABLED=0`; init audio tidak memblok startup;
+degradasi anggun tanpa audio device; ukur latensi.
+
+## Cara menjalankan ulang
+
+```bash
+# Skenario 1 — live (butuh PulseAudio/PipeWire)
+TIA_AUDIO_SPIKE=1 go test ./internal/audio/ -run TestEngineSpike -v -count=1
+
+# Skenario 2 — pulse rusak → fallback ALSA
+TIA_AUDIO_SPIKE=1 PULSE_SERVER=unix:/nonexistent go test ./internal/audio/ -run TestEngineSpike -v -count=1
+
+# Skenario 3 — pulse + ALSA rusak → degradasi total (tidak boleh panic)
+TIA_AUDIO_SPIKE=1 PULSE_SERVER=unix:/nonexistent ALSA_CONFIG_PATH=/nonexistent/asound.conf \
+  go test ./internal/audio/ -run TestEngineSpike -v -count=1
+```
+
+## Hasil
+
+| # | Skenario | `New()` return | Init + ready | `Play()` return | Status |
+|---|---|---|---|---|---|
+| 1 | Live (PipeWire/pulse socket) | **1.5 µs** | **13.3 ms** | **5.7 – 15.7 µs** | `siap` ✅ |
+| 2 | Pulse rusak → fallback ALSA | 3.1 µs | 26.1 ms | 7 – 12 µs | `siap` (via ALSA) ✅ |
+| 3 | Pulse + ALSA rusak | 2.1 µs | 0.4 ms (gagal cepat) | no-op | `gagal: ...` tanpa panic ✅ |
+
+- Binary **6.7 MB** (`CGO_ENABLED=0`), aset 8 WAV embedded = **128 KB** (budget PRD < 2 MB ✓).
+- Target PRD: startup < 500 ms → audio init async hanya **1.5 µs** di jalur startup ✓;
+  latensi suara < 100 ms → pemanggilan `Play()` ~10 µs, latency terdengar mengikuti buffer device.
+- TUI menampilkan status engine live: `audio: menyiapkan…` → `siap` setelah redraw pertama.
+
+## Temuan penting
+
+1. **`purego` (dipakai driver ALSA oto) membuat binary link dinamis ke glibc.**
+   Uji kontrol: hello-world `CGO_ENABLED=0` = `statically linked` murni; begitu oto ikut
+   di-compile muncul `libc.so.6`, `libdl`, `libpthread`. Artinya: tetap **satu file & tanpa
+   cgo**, tapi belum `statically linked` penuh. **Alpine/musl belum terverifikasi** → catat
+   sebagai risiko; jalur keluar bila perlu: build varian tanpa driver ALSA (pulse-only).
+2. **Fallback berantai terbukti**: PulseAudio (pure-Go) → ALSA (purego dlopen `libasound.so.2`)
+   → error jelas. Pesan error oto ditampilkan apa adanya (sesuai F-023; penjelasan i18n menyusul).
+3. Auto-mute SSH diuji di unit test (`SSH_CONNECTION` → `muted`), belum diuji di sesi SSH asli.
+
+## Batasan (jujur)
+
+- Latensi *terdengar* tidak diukur programatik (butuh loopback/ears) — yang diukur waktu init
+  & waktu `Play()` kembali. Buffer device oto masih default; bila klik terasa delay di hardware
+  nyata, set `BufferSize` (Phase 1).
+- Belum diuji di macOS, WSL2, dan sesi SSH asli.
+
+## Status follow-up
+
+- [ ] Ganti aset placeholder dengan Kenney CC0 (T-0.6)
+- [ ] Toggle suara/volume langsung dari layar Pengaturan tanpa restart (Phase 1, F-024)
+- [ ] `tia-love doctor` menampilkan status audio (Phase 1)

go.mod

@@ -5,6 +5,7 @@ go 1.27.1
 require (
 	charm.land/bubbletea/v2 v2.1.0
 	charm.land/lipgloss/v2 v2.0.6
+	github.com/ebitengine/oto/v3 v3.5.1
 )
 
 require (
@@ -16,6 +17,8 @@ require (
 	github.com/charmbracelet/x/windows v0.2.2 // indirect
 	github.com/clipperhouse/displaywidth v0.11.0 // indirect
 	github.com/clipperhouse/uax29/v2 v2.7.0 // indirect
+	github.com/ebitengine/purego v0.11.0 // indirect
+	github.com/jfreymuth/pulse v0.1.3 // indirect
 	github.com/lucasb-eyer/go-colorful v1.4.1 // indirect
 	github.com/mattn/go-runewidth v0.0.30 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect

go.sum

@@ -22,6 +22,12 @@ github.com/clipperhouse/displaywidth v0.11.0 h1:lBc6kY44VFw+TDx4I8opi/EtL9m20WSE
 github.com/clipperhouse/displaywidth v0.11.0/go.mod h1:bkrFNkf81G8HyVqmKGxsPufD3JhNl3dSqnGhOoSD/o0=
 github.com/clipperhouse/uax29/v2 v2.7.0 h1:+gs4oBZ2gPfVrKPthwbMzWZDaAFPGYK72F0NJv2v7Vk=
 github.com/clipperhouse/uax29/v2 v2.7.0/go.mod h1:EFJ2TJMRUaplDxHKj1qAEhCtQPW2tJSwu5BF98AuoVM=
+github.com/ebitengine/oto/v3 v3.5.1 h1:7gL5DxxSQp8S1Me2jDSp+gSAyondYxpjM5RPBBqLT0c=
+github.com/ebitengine/oto/v3 v3.5.1/go.mod h1:Elkm7yzTRns3w2efvibzVOoQ65YOwmec9a76dCiK10o=
+github.com/ebitengine/purego v0.11.0 h1:jhp/D+Nyv7UUW8HAcmcjt2N2rYrYi9m3SL21k0Ua/NI=
+github.com/ebitengine/purego v0.11.0/go.mod h1:DCHPP08djqhNSoTfImcnHYQRZmd0qhakvrozqaEYhGQ=
+github.com/jfreymuth/pulse v0.1.3 h1:bc5TdxiB8E+2INnFjFWWgyfgXtz2IyNNNCX+Wt/ZD14=
+github.com/jfreymuth/pulse v0.1.3/go.mod h1:cpYspI6YljhkUf1WLXLLDmeaaPFc3CnGLjDZf9dZ4no=
 github.com/lucasb-eyer/go-colorful v1.4.1 h1:1EO+WB73+EH8EVbzlrG3KLAfEypQWVHIBqlTf+2hNss=
 github.com/lucasb-eyer/go-colorful v1.4.1/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mattn/go-runewidth v0.0.30 h1:+KUuiDA4fF0R1p5FeueHefjDm+GIM+kWfFnDjybOPgk=

internal/app/app.go

@@ -5,19 +5,25 @@ import (
 
 	tea "charm.land/bubbletea/v2"
 	"charm.land/lipgloss/v2"
+
+	"github.com/oxpoe/tia/internal/audio"
 )
 
-// Model root sementara (T-0.2, Phase 0).
-// Tujuannya membuktikan Bubble Tea v2 (View struct, mouse, resize) sebelum
-// layout penuh Phase 1 menggantikannya.
+// Model root sementara (T-0.2/T-0.3, Phase 0).
+// Membuktikan Bubble Tea v2 (View struct, mouse, resize) + audio engine
+// sebelum layout penuh Phase 1 menggantikannya.
 type Model struct {
 	width, height int
 	clicks        int
 	lastClick     string
+	sound         *audio.Engine
 }
 
 func New() Model {
-	return Model{lastClick: "belum ada klik"}
+	return Model{
+		lastClick: "belum ada klik",
+		sound:     audio.New(audio.Options{Enabled: true, Volume: 70, MuteOnSSH: true}),
+	}
 }
 
 func (m Model) Init() tea.Cmd { return nil }
@@ -30,13 +36,17 @@ func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 	case tea.KeyPressMsg:
 		switch msg.String() {
 		case "q", "ctrl+c", "esc":
+			m.sound.Play(audio.ModalClose)
 			return m, tea.Quit
+		case "j", "down", "k", "up":
+			m.sound.Play(audio.Navigate)
 		}
 
 	case tea.MouseClickMsg:
 		if msg.Button == tea.MouseLeft {
 			m.clicks++
 			m.lastClick = fmt.Sprintf("klik #%d di (%d, %d)", m.clicks, msg.X, msg.Y)
+			m.sound.Play(audio.Click)
 		}
 	}
 	return m, nil
@@ -49,15 +59,15 @@ func (m Model) View() tea.View {
 		Render("tia — Terminal Is A My Way")
 	tagline := lipgloss.NewStyle().
 		Foreground(lipgloss.Color("#a6adc8")).
-		Render("Just Work · Phase 0 · skeleton TUI")
+		Render("Just Work · Phase 0 · skeleton TUI + audio")
 	box := lipgloss.NewStyle().
 		Border(lipgloss.RoundedBorder()).
 		BorderForeground(lipgloss.Color("#6c7086")).
 		Padding(0, 2).
-		Render(m.lastClick + "\n\nklik mouse di mana saja · tekan q untuk keluar")
+		Render(m.lastClick + "\n\nklik / j / k = bunyi · q = keluar")
 
-	content := fmt.Sprintf("%s\n%s\n\n%s\n\nukuran jendela: %dx%d",
-		title, tagline, box, m.width, m.height)
+	content := fmt.Sprintf("%s\n%s\n\n%s\n\nukuran jendela: %dx%d · audio: %s",
+		title, tagline, box, m.width, m.height, m.sound.Status())
 
 	v := tea.NewView(content)
 	v.AltScreen = true

internal/audio/audio.go

@@ -0,0 +1,181 @@
+// Package audio — efek suara interaktif (F-024).
+//
+// Inisialisasi asynchronous: New() tidak pernah memblok startup.
+// Bila tidak ada audio device/server, engine tetap hidup dan Play() menjadi
+// no-op (degradasi anggun); Status() dipakai status bar & `tia-love doctor`.
+package audio
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/ebitengine/oto/v3"
+)
+
+type Options struct {
+	Enabled   bool
+	Volume    int // 0-100
+	MuteOnSSH bool
+}
+
+type Engine struct {
+	opts  Options
+	muted bool
+	ready chan struct{}
+
+	mu      sync.RWMutex
+	ctx     *oto.Context
+	sounds  map[Event][]byte
+	initErr error
+}
+
+const initTimeout = 3 * time.Second
+
+// New membuat Engine dan — bila aktif — memulai init audio di goroutine
+// terpisah sehingga waktu startup aplikasi tidak terpengaruh.
+//
+// shortcut: engine yang disabled/muted tidak dapat diaktifkan ulang tanpa
+// restart; upgrade saat layar Pengaturan (Phase 1, F-024) butuh toggle langsung.
+func New(opts Options) *Engine {
+	e := &Engine{
+		opts:  opts,
+		ready: make(chan struct{}),
+		muted: opts.MuteOnSSH && InSSHSession(),
+	}
+	switch {
+	case !opts.Enabled:
+		e.setErr(errors.New("efek suara dimatikan"))
+		close(e.ready)
+	case e.muted:
+		e.setErr(errors.New("auto-mute: sesi SSH"))
+		close(e.ready)
+	default:
+		go e.init()
+	}
+	return e
+}
+
+func (e *Engine) init() {
+	defer close(e.ready)
+
+	sounds, err := loadSounds()
+	if err != nil {
+		e.setErr(err)
+		return
+	}
+	ctx, readyCh, err := oto.NewContext(&oto.NewContextOptions{
+		SampleRate:   44100,
+		ChannelCount: 1,
+		Format:       oto.FormatSignedInt16LE,
+	})
+	if err != nil {
+		e.setErr(err)
+		return
+	}
+	select {
+	case <-readyCh:
+	case <-time.After(initTimeout):
+		e.setErr(errors.New("audio: device tidak siap dalam 3 detik"))
+		return
+	}
+	if err := ctx.Err(); err != nil {
+		e.setErr(err)
+		return
+	}
+	e.mu.Lock()
+	e.ctx, e.sounds = ctx, sounds
+	e.mu.Unlock()
+}
+
+func (e *Engine) setErr(err error) {
+	e.mu.Lock()
+	e.initErr = err
+	e.mu.Unlock()
+}
+
+// Ready melaporkan apakah audio benar-benar siap memutar suara.
+func (e *Engine) Ready() bool {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.ctx != nil
+}
+
+// Err mengembalikan penyebab engine tidak siap (nil bila siap/ masih init).
+func (e *Engine) Err() error {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.initErr
+}
+
+// Muted: auto-mute karena sesi SSH.
+func (e *Engine) Muted() bool { return e.muted }
+
+// WaitReady menunggu init selesai (untuk tes & `doctor`).
+func (e *Engine) WaitReady(d time.Duration) bool {
+	select {
+	case <-e.ready:
+	case <-time.After(d):
+		return false
+	}
+	return e.Ready()
+}
+
+// Status ringkas untuk status bar / `tia-love doctor`.
+func (e *Engine) Status() string {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	switch {
+	case e.muted:
+		return "SSH auto-mute"
+	case !e.opts.Enabled:
+		return "nonaktif"
+	case e.ctx != nil:
+		return "siap"
+	case e.initErr != nil:
+		return "gagal: " + e.initErr.Error()
+	default:
+		return "menyiapkan…"
+	}
+}
+
+// Play memutar efek; fire-and-forget, aman dipanggil dari goroutine mana pun.
+// No-op bila engine belum siap / dimatikan / muted.
+func (e *Engine) Play(ev Event) {
+	if e.muted || !e.opts.Enabled {
+		return
+	}
+	e.mu.RLock()
+	ctx, pcm := e.ctx, e.sounds[ev]
+	e.mu.RUnlock()
+	if ctx == nil || len(pcm) == 0 {
+		return
+	}
+	vol := float64(e.opts.Volume) / 100
+	if vol < 0 {
+		vol = 0
+	} else if vol > 1 {
+		vol = 1
+	}
+	p := ctx.NewPlayer(bytes.NewReader(pcm))
+	p.SetVolume(vol)
+	p.Play()
+	go func() {
+		for p.IsPlaying() {
+			time.Sleep(5 * time.Millisecond)
+		}
+		_ = p.Close()
+	}()
+}
+
+// InSSHSession mendeteksi sesi SSH lewat env standar.
+func InSSHSession() bool {
+	for _, k := range []string{"SSH_CONNECTION", "SSH_CLIENT", "SSH_TTY"} {
+		if os.Getenv(k) != "" {
+			return true
+		}
+	}
+	return false
+}

internal/audio/audio_test.go

@@ -0,0 +1,77 @@
+package audio
+
+import (
+	"os"
+	"testing"
+	"time"
+)
+
+func TestInSSHSession(t *testing.T) {
+	t.Setenv("SSH_CONNECTION", "")
+	t.Setenv("SSH_CLIENT", "")
+	t.Setenv("SSH_TTY", "")
+	if InSSHSession() {
+		t.Fatal("harusnya false tanpa env SSH")
+	}
+	t.Setenv("SSH_CONNECTION", "10.0.0.1 22")
+	if !InSSHSession() {
+		t.Fatal("harusnya true dengan SSH_CONNECTION")
+	}
+}
+
+func TestEngineDisabledGraceful(t *testing.T) {
+	e := New(Options{Enabled: false})
+	if e.Ready() {
+		t.Fatal("engine disabled tidak boleh ready")
+	}
+	if got := e.Status(); got != "nonaktif" {
+		t.Fatalf("status: %q", got)
+	}
+	e.Play(Click) // tidak boleh panic
+	e.Play(Navigate)
+}
+
+func TestEngineSSHMute(t *testing.T) {
+	t.Setenv("SSH_CONNECTION", "10.0.0.1 22")
+	e := New(Options{Enabled: true, MuteOnSSH: true})
+	if !e.Muted() {
+		t.Fatal("harusnya muted di sesi SSH")
+	}
+	if got := e.Status(); got != "SSH auto-mute" {
+		t.Fatalf("status: %q", got)
+	}
+	e.Play(Click) // no-op
+}
+
+// TestEngineSpike — bukti Phase 0 (T-0.3). Jalankan manual:
+//
+//	TIA_AUDIO_SPIKE=1 go test ./internal/audio/ -run TestEngineSpike -v -count=1
+//
+// Mengukur init (harus non-blocking) dan memastikan Play() cepat + tidak panic.
+// Tanpa audio device, test tetap lulus sebagai bukti degradasi anggun.
+func TestEngineSpike(t *testing.T) {
+	if os.Getenv("TIA_AUDIO_SPIKE") != "1" {
+		t.Skip("set TIA_AUDIO_SPIKE=1 untuk menjalankan spike audio")
+	}
+
+	t0 := time.Now()
+	e := New(Options{Enabled: true, Volume: 70})
+	t.Logf("New() kembali dalam %v (non-blocking)", time.Since(t0))
+
+	t1 := time.Now()
+	ok := e.WaitReady(5 * time.Second)
+	t.Logf("init+ready selesai dalam %v (ready=%v, status=%q, err=%v)", time.Since(t1), ok, e.Status(), e.Err())
+
+	if !ok {
+		// Skenario tanpa audio device: cukup buktikan tidak panic.
+		e.Play(Click)
+		return
+	}
+	for _, ev := range []Event{Click, Navigate, NotifySuccess} {
+		t2 := time.Now()
+		e.Play(ev)
+		t.Logf("Play(%s) kembali dalam %v", ev, time.Since(t2))
+		time.Sleep(150 * time.Millisecond)
+	}
+	time.Sleep(400 * time.Millisecond)
+}

internal/audio/sounds.go

@@ -0,0 +1,43 @@
+package audio
+
+import (
+	"embed"
+	"fmt"
+)
+
+//go:embed assets/*.wav
+var assets embed.FS
+
+// Event — jenis efek suara (F-024).
+type Event string
+
+const (
+	Click         Event = "click"
+	Navigate      Event = "navigate"
+	ModalOpen     Event = "modal_open"
+	ModalClose    Event = "modal_close"
+	NotifySuccess Event = "notify_success"
+	NotifyWarning Event = "notify_warning"
+	NotifyError   Event = "notify_error"
+	Exec          Event = "exec"
+)
+
+var allEvents = []Event{Click, Navigate, ModalOpen, ModalClose, NotifySuccess, NotifyWarning, NotifyError, Exec}
+
+// loadSounds membaca + memvalidasi semua aset sekali di awal; PCM di-cache
+// supaya Play() tidak menyentuh disk/embed FS.
+func loadSounds() (map[Event][]byte, error) {
+	out := make(map[Event][]byte, len(allEvents))
+	for _, ev := range allEvents {
+		raw, err := assets.ReadFile("assets/" + string(ev) + ".wav")
+		if err != nil {
+			return nil, err
+		}
+		pcm, err := ParsePCM(raw)
+		if err != nil {
+			return nil, fmt.Errorf("%s.wav: %w", ev, err)
+		}
+		out[ev] = pcm
+	}
+	return out, nil
+}

internal/audio/wav.go

@@ -0,0 +1,51 @@
+package audio
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+)
+
+// ParsePCM memvalidasi file WAV (RIFF) dan mengembalikan isi chunk "data" (PCM).
+// Standar aset tia (PRD Appendix C): 44.1 kHz, mono, 16-bit — selain itu ditolak
+// agar kesalahan aset ketahuan saat dev, bukan saat runtime.
+func ParsePCM(b []byte) ([]byte, error) {
+	if len(b) < 44 || string(b[0:4]) != "RIFF" || string(b[8:12]) != "WAVE" {
+		return nil, errors.New("bukan file RIFF/WAVE")
+	}
+	var (
+		format, channels, bits, rate int
+		data                         []byte
+	)
+	for off := 12; off+8 <= len(b); {
+		id := string(b[off : off+4])
+		size := int(binary.LittleEndian.Uint32(b[off+4 : off+8]))
+		off += 8
+		if size < 0 || off+size > len(b) {
+			return nil, fmt.Errorf("chunk %q terpotong", id)
+		}
+		switch id {
+		case "fmt ":
+			if size < 16 {
+				return nil, errors.New("chunk fmt terlalu pendek")
+			}
+			format = int(binary.LittleEndian.Uint16(b[off : off+2]))
+			channels = int(binary.LittleEndian.Uint16(b[off+2 : off+4]))
+			rate = int(binary.LittleEndian.Uint32(b[off+4 : off+8]))
+			bits = int(binary.LittleEndian.Uint16(b[off+14 : off+16]))
+		case "data":
+			data = b[off : off+size]
+		}
+		off += size + size%2 // chunk berukuran ganjil dipad 1 byte
+	}
+	if format != 1 {
+		return nil, fmt.Errorf("format %d bukan PCM", format)
+	}
+	if channels != 1 || bits != 16 || rate != 44100 {
+		return nil, fmt.Errorf("hanya mono/16-bit/44100Hz didukung (dapat %dch/%dbit/%dHz)", channels, bits, rate)
+	}
+	if len(data) == 0 {
+		return nil, errors.New("chunk data kosong")
+	}
+	return data, nil
+}

internal/audio/wav_test.go

@@ -0,0 +1,53 @@
+package audio
+
+import (
+	"encoding/binary"
+	"testing"
+)
+
+// wavBytes merakit WAV minimal (RIFF/WAVE + fmt + data) untuk pengujian parser.
+func wavBytes(channels, bits, rate int, data []byte) []byte {
+	b := make([]byte, 0, 44+len(data))
+	b = append(b, "RIFF"...)
+	b = binary.LittleEndian.AppendUint32(b, uint32(36+len(data)))
+	b = append(b, "WAVE"...)
+	b = append(b, "fmt "...)
+	b = binary.LittleEndian.AppendUint32(b, 16)                           // ukuran fmt
+	b = binary.LittleEndian.AppendUint16(b, 1)                            // PCM
+	b = binary.LittleEndian.AppendUint16(b, uint16(channels))             // kanal
+	b = binary.LittleEndian.AppendUint32(b, uint32(rate))                 // sample rate
+	b = binary.LittleEndian.AppendUint32(b, uint32(rate*channels*bits/8)) // byte rate
+	b = binary.LittleEndian.AppendUint16(b, uint16(channels*bits/8))      // block align
+	b = binary.LittleEndian.AppendUint16(b, uint16(bits))                 // bit/sample
+	b = append(b, "data"...)
+	b = binary.LittleEndian.AppendUint32(b, uint32(len(data)))
+	return append(b, data...)
+}
+
+func TestParsePCM(t *testing.T) {
+	pcm := []byte{1, 0, 2, 0, 3, 0, 4, 0}
+
+	got, err := ParsePCM(wavBytes(1, 16, 44100, pcm))
+	if err != nil {
+		t.Fatalf("wav valid ditolak: %v", err)
+	}
+	if string(got) != string(pcm) {
+		t.Fatalf("PCM tidak sama: %v", got)
+	}
+
+	cases := []struct {
+		name string
+		b    []byte
+	}{
+		{"bukan RIFF", []byte("NOPE-nope-nope-nope-nope-nope-nope-nope-nope")},
+		{"stereo", wavBytes(2, 16, 44100, pcm)},
+		{"sample rate salah", wavBytes(1, 16, 48000, pcm)},
+		{"bit depth salah", wavBytes(1, 8, 44100, pcm)},
+		{"data kosong", wavBytes(1, 16, 44100, nil)},
+	}
+	for _, c := range cases {
+		if _, err := ParsePCM(c.b); err == nil {
+			t.Errorf("%s: seharusnya error", c.name)
+		}
+	}
+}