public void TestForTwo()
        {
            AreaOfTheCircle circle = new AreaOfTheCircle();

            circle.Radius = 2;
            var area = circle.CalculateArea();

            Assert.AreEqual(12.56, area, "R=1");
        }
        public void TestForMinValue()
        {
            AreaOfTheCircle circle = new AreaOfTheCircle();

            circle.Radius = double.MinValue;
            var area = circle.CalculateArea();

            Assert.Fail();
        }
        public void TestForNegOne()
        {
            AreaOfTheCircle circle = new AreaOfTheCircle();

            circle.Radius = -1;
            var area = circle.CalculateArea();

            Assert.Fail();
        }
        public void TestForOne()
        {
            AreaOfTheCircle circle = new AreaOfTheCircle();

            circle.Radius = 1;
            var area = circle.CalculateArea();

            Assert.AreEqual(3.14, area, "R=3.14");
        }
        public void TestForMaxValue()
        {
            //1.8 × 10308
            AreaOfTheCircle circle = new AreaOfTheCircle();

            circle.Radius = double.MaxValue;
            var area = circle.CalculateArea();

            Assert.Fail();
        }