public void buyBeerTest()
        {
            Beer beer = new Beer();

            customer.buy(beer);
            string actual = customer.print();
            string expect = "Beer(18.00) | Total=18.00";

            Assert.AreEqual(expect, actual);
        }
        public void buyBeerAndLoversEmbraceTest()
        {
            Beer beer = new Beer();
            LoversEmbrace loversEmbrace = new LoversEmbrace();

            customer.buy(beer);
            customer.buy(loversEmbrace);

            string actual = customer.print();
            string expect = "Beer(18.00)+LoversEmbrace(21.00*80%) | Total=34.80";

            Assert.AreEqual(expect, actual);
        }
        public void buyBeerAndLemon()
        {
            Beer beer = new Beer();
            Lemon lemon = new Lemon();

            customer.buy(beer);
            customer.buy(lemon);

            string actual = customer.print();
            string expect = "Beer(18.00)+Lemon(5.00) | Total=23.00";

            Assert.AreEqual(expect, actual);
        }