public void test_currency_exchange_to_another_currency() { //Given var usd = Currency.Create("USD", 2); var fiveTWD = FakeMoneyBuilder.CreateTWD(5); //When var bucks = exchange.ExchangeTo(fiveTWD, usd); //Then Assert.True(bucks.Currency.Equals(usd)); Assert.Equal(1, bucks.Amount); }