public void TwentyFor4X5RectangleFromSquare()
        {
            Rectangle newRectangle = new Square();

            newRectangle.Width  = 4;
            newRectangle.Height = 5;
            Assert.AreEqual(20, AreaCalculator.CalculateArea(newRectangle));
        }
        public void SixFor2X3Rectangle()
        {
            var myRectangle = new Rectangle {
                Height = 2, Width = 3
            };

            Assert.AreEqual(6, AreaCalculator.CalculateArea(myRectangle));
        }
        public void NineFor3X3Square()
        {
            var mySquare = new Square()
            {
                Height = 3
            };

            Assert.AreEqual(9, AreaCalculator.CalculateArea(mySquare));
        }