Testing the power-up system implementation

To quickly test our implementation in your own instance of Unity, you need to follow these steps:

1. Copy all the scripts we just reviewed into your Unity project.
2. Create a new scene.
3. Add a GameObject to the scene.
4. Attach the following ClientVisitor script to the new GameObject:

using UnityEngine;

namespace Pattern.Visitor
{
    public class ClientVisitor : MonoBehaviour
    {
        public PowerUp enginePowerUp;
        public PowerUp shieldPowerUp;
        public PowerUp weaponPowerUp;

        private BikeController _bikeController;

        void Start()
        {
            _bikeController = 
                gameObject.
                    AddComponent<BikeController>();
        }

        void OnGUI()
        {
            if (GUILayout.Button("PowerUp Shield"))
                _bikeController.Accept(shieldPowerUp);

            if (GUILayout.Button("PowerUp Engine"))
                _bikeController.Accept(enginePowerUp);

            if...