Add audio device switching UI

internal/page/AudioDevices_test.go

@@ -0,0 +1,36 @@
+package page
+
+import (
+	"testing"
+
+	"rhemawavetech.com/rhemawave/internal/mixer"
+)
+
+func TestCurrentDeviceIndex(t *testing.T) {
+	devices := []mixer.Device{
+		{Name: "Built-in Audio Analog Stereo", Label: "Internal Speakers"},
+		{Name: "Built-in Audio Digital Stereo (HDMI)", Label: "HDMI | Monitor | TV"},
+	}
+
+	tests := []struct {
+		name        string
+		devices     []mixer.Device
+		currentName string
+		want        int
+	}{
+		{"empty list, default device", nil, "", 0},
+		{"empty list, named device", nil, "USB Audio", -1},
+		{"default device", devices, "", 0},
+		{"exact first device match", devices, "Built-in Audio Analog Stereo", 1},
+		{"exact second device match", devices, "Built-in Audio Digital Stereo (HDMI)", 2},
+		{"no match", devices, "USB Audio", -1},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := currentDeviceIndex(tt.devices, tt.currentName); got != tt.want {
+				t.Errorf("currentDeviceIndex(%v, %q) = %d, want %d", tt.devices, tt.currentName, got, tt.want)
+			}
+		})
+	}
+}