画像を反復するためのクラスがあります。
public class PictureManager
    {
        private int _current;
        public List<BitmapImage> _images = new List<BitmapImage>(5);
        public static string ImagePath = "dataImages";
        public async void LoadImages()
        {
            _images = await GetImagesAsync();
        }
        public async Task<List<BitmapImage>> GetImagesAsync()
        {
            var files = new List<BitmapImage>();
            StorageFolder picturesFolder = await KnownFolders.PicturesLibrary.GetFolderAsync("dataImages");
            IReadOnlyList<IStorageItem> itemsList = await picturesFolder.GetItemsAsync();
            foreach(var item in itemsList)
            {
                if(!(item is StorageFile)) continue;
                var tempImage = new BitmapImage(new Uri(item.Path));
                Debug.WriteLine(string.Format("add {0}", item.Path));
                files.Add(tempImage);
            }
            return files;
        }
}
そして、私はこのテストメソッドを書きます(私はnUnitを使用しています):
  [TestFixture]
    public class PictureManagerTest
    {
        private PictureManager _pic;
        [SetUp]
        public void Init()
        {
            _pic = new PictureManager();
            _pic.LoadImages();
        }
        [Test]
        public void ElementOfImagesIsNotNull()
        {
            _pic.GetImagesAsync().ContinueWith(r =>
            {
                BitmapImage image = r.Result[0];
                image = null;
                Assert.IsNotNull(image);
            });
        }
}
このテストが成功する理由