public void Test(string productName)
        {
            var product = Facotry.Make(productName);

            product.ShouldNotBeNull();
            product.Name.ShouldBe(productName);
        }
 public void TestError()
 {
     Assert.Throws <ArgumentNullException>(() => Facotry.Make(null));
     Assert.Throws <ArgumentException>(() => Facotry.Make("Nothing"));
 }