ocp minimaliste

gistfile1.java

public class BillFormatter {

    public String format(int price, Currency currency) throws UnknownCurrencyException {
        String formattedPrice = "Your total is : ";
        if (currency == Currency.EUROS) {
            formattedPrice += price + "€";
        } else if (currency == Currency.POUNDS) {
            formattedPrice += "£" + price;
        } else {
            throw new UnknownCurrencyException();
        }
        return formattedPrice;
    }
}

=====================
public class BillFormatterTest {
    @Test
    public void handlesPounds() throws Exception {
        BillFormatter billFormatter = new BillFormatter();
        String price = billFormatter.format(100, Currency.POUNDS);
        assertThat(price, endsWith("£100"));
    }
    @Test
    public void handlesEuros() throws Exception {
        BillFormatter billFormatter = new BillFormatter();
        String price = billFormatter.format(23, Currency.EUROS);
        assertThat(price, endsWith("23€"));
    }
}