### Question:
NoOpExchangeRateCalculator implements ExchangeRateCalculator { @Override public UnsignedLong calculateMinAmountToAccept( final UnsignedLong sendAmount, final Denomination sendAmountDenomination ) { Objects.requireNonNull(sendAmount); Objects.requireNonNull(sendAmountDenomination); return UnsignedLong.ZERO; }  @Override UnsignedLong calculateAmountToSend(UnsignedLong amountToSend,
      Denomination amountToSendDenomination,
      Denomination receiverDenomination); @Override UnsignedLong calculateMinAmountToAccept(
      final UnsignedLong sendAmount, final Denomination sendAmountDenomination
  );  }### Answer:
@Test public void calculateMinAmountToAcceptInReceiverAmountMode() { ExchangeRateCalculator calc = new NoOpExchangeRateCalculator(); assertThat(calc.calculateMinAmountToAccept(UnsignedLong.ONE, Denominations.USD, Denominations.EUR)) .isEqualTo(UnsignedLong.ZERO); }
@Test public void calculateMinAmountToAcceptInSenderAmountMode() { ExchangeRateCalculator calc = new NoOpExchangeRateCalculator(); assertThat(calc.calculateMinAmountToAccept(UnsignedLong.ONE, Denominations.USD)) .isEqualTo(UnsignedLong.ZERO); }