public void ExecuteTest()
{
var user = new User("test", "test", "test", "*****@*****.**", 99);
var product1 = new BuyTransaction(DateTime.Now, user, new Product("test", 100, true));
var product2 = new BuyTransaction(DateTime.Now, user, new Product("test", 0, false));
Assert.Throws<InsufficientCreditsException>(new TestDelegate(() => { product1.Execute(); }));
Assert.Throws<NotActiveException>(new TestDelegate(() => { product2.Execute(); }));
}
