public void Test1()
        {
            var stocks = new [] { 1, 2, 3, 4, 5 };

            var result = StockBuying.MaxProfit(stocks);

            Assert.That(result, Is.EqualTo(4));
        }
        public void Test2()
        {
            var stocks = new [] { 7, 1, 5, 3, 6, 4 };

            var result = StockBuying.MaxProfit(stocks);

            Assert.That(result, Is.EqualTo(5));
        }