### Question:
CurrencyConverter { public BigDecimal convert(BigDecimal amount, String currencyFrom, String currencyTo) { BigDecimal exchangeRate = currencyDto.getExchangeRate(currencyFrom, currencyTo); return amount.multiply(exchangeRate); } CurrencyConverter(CurrencyDto currencyDto); static CurrencyConverter get(); BigDecimal convert(BigDecimal amount, String currencyFrom, String currencyTo);  }### Answer:
@Test public void test01() { Assertions.assertEquals(converter.convert(BigDecimal.TEN, "EUR", "USD"), new BigDecimal("100")); Assertions.assertTrue(currencyDto.isMethodCalled()); }
@Test public void resultIsUsd() { convertedAmmount = converter.convert(BigDecimal.TEN, "EUR", "CAN"); Assertions.assertEquals(new BigDecimal("100"), convertedAmmount); }