@Test
public void testSimpleAddition() {
Expression five = Money.dollar(5);
Expression sum = five.plus(five);
Bank bank = new Bank();
Money reduced = bank.reduce(sum, USD);
assertEquals(Money.dollar(10), reduced);
}
@Test
public void testPlusReturnsSum() {
Expression five = Money.dollar(5);
Expression result = five.plus(five);
Sum sum = (Sum) result;
assertEquals(five, sum.augend);
assertEquals(five, sum.addend);
}
@Test
public void testPlusSameCurrencyReturnsMoney() {
Money result = Money.dollar(1).plus(Money.dollar(1));
assertEquals(Money.dollar(2), result);
}
@Test
public void testReduce() {
Money dollar = Money.dollar(1);
Money reduce = dollar.reduce(new Bank(), dollar.currency());
assertEquals(dollar, reduce);
}
@Test
public void testCurrency() {
assertEquals(USD, Money.dollar(1).currency());
assertEquals(CHF, Money.franc(1).currency());
}
@Test
public void testEquality() {
Money fiveFrancs = Money.franc(5);
Money fiveDollars = Money.dollar(5);
assertFalse(fiveFrancs.equals(fiveDollars));
}