test: verify default audio lifecycle

runtime/tests/p9_0r3_audio_lifecycle_test.gd

@@ -0,0 +1,39 @@
+extends SceneTree
+
+const MainScene = preload("res://main.tscn")
+
+var failures: Array[String] = []
+
+
+func _initialize() -> void:
+	call_deferred("run_test")
+
+
+func run_test() -> void:
+	var game := MainScene.instantiate()
+	game.auto_boot = false
+	root.add_child(game)
+	await settle(12)
+	expect(game.audio_enabled, "runtime audio remains enabled by default")
+	expect(game.audio_player != null, "default runtime creates the SFX player")
+	expect(game.audio_player != null and game.audio_player.playing, "default SFX stream is playing")
+	expect(game.sfx_playback != null, "default SFX stream exposes playback")
+	game.queue_free()
+	await settle(120)
+	if failures.is_empty():
+		print("ABG_P9_0R3_AUDIO_LIFECYCLE_OK default_enabled=true stream=true cleanup=true")
+		quit(0)
+	else:
+		for failure in failures:
+			push_error(failure)
+		quit(1)
+
+
+func settle(frames: int) -> void:
+	for frame in range(frames):
+		await process_frame
+
+
+func expect(condition: bool, message: String) -> void:
+	if not condition:
+		failures.append("P9.0R3 audio lifecycle: %s" % message)