public void HiddingTest()
        {
            // arrange
            BorderWindow Test = new BorderWindow();

            Grid[] WallsFloor = new Grid[70];
            Grid   Wall1      = new Grid();

            Wall1.Opacity  = 100;
            WallsFloor[50] = Wall1;
            int    i    = 50;
            double wall = 100;

            // act
            Test.Hidding(i);

            // assert
            double wall2 = WallsFloor[50].Opacity;

            Assert.AreEqual(wall2, wall, "nie schowano");
        }