public void TestReduceSum()
{
Expression sum = new Sum(Money.CreateDollar(3), Money.CreateDollar(4));
Bank bank = new Bank();
Money result = bank.Reduce(sum, "USD");
Assert.AreEqual(Money.CreateDollar(7), result);
}
public void TestSumTimes()
{
Expression fiveDollars = Money.CreateDollar(5);
Expression tenFrancs = Money.CreateFranc(10);
Bank bank = new Bank();
bank.AddRate("CHF", "USD", 2);
Expression sum = new Sum(fiveDollars, tenFrancs).Times(2);
Money result = bank.Reduce(sum, "USD");
Assert.AreEqual(Money.CreateDollar(20), result);
}