// Update is called once per frame
    void Update()
    {
        played = CompleteMetalGame.checkSuccess();

        if (played)
        {
            if (showIcon)
            {
                animation.Play("wellDone");
                successSource.Play();
                showIcon = false;
            }
            Invoke("nextScene", 1);
        }
    }
    // Test for play WellDone animation & audio, and check if game is success when all items are removed

    public IEnumerator testPlayWellDone()
    {
        items    = GameObject.FindGameObjectsWithTag("item");
        wellDone = GameObject.Find("wellDone");
        wellDone.GetComponent <AudioSource> ().volume = 0;              // mute the audioSouce

        foreach (GameObject obj in items)
        {
            obj.GetComponent <DragItem> ().Invoke("OnMouseUp", 0);
        }
        ;
        yield return(new WaitForSeconds(0.5f));

        Assert.IsTrue(CompleteMetalGame.checkSuccess());
        Assert.IsTrue(wellDone.GetComponent <Animation> ().IsPlaying("wellDone"));
        Assert.IsTrue(wellDone.GetComponent <AudioSource> ().isPlaying);
        yield return(null);
    }