public ICommandLineParser Parse(string[] args)
{
if (ArgsAreNotValid(args))
{
return(this);
}
var currencyPair = args[0].Split("/");
if (currencyPair.Length != 2)
{
Error = Constants.CurrencyPairIncorrectFormat;
return(this);
}
if (!int.TryParse(args[1], out var result))
{
Error = Constants.UnableToParseAmount;
return(this);
}
ParsedObject = new FxExchange
{
CurrencyPair = new CurrencyPair
{
From = currencyPair[0],
To = currencyPair[1]
},
Amount = result
};
return(this);
}
public void Exchange_ShouldThrow_WhenCurrencyIsNotFound(FxExchange exchange, IExchangeRateHolder rateHolder)
{
// arrange
var sut = new CurrencyExchanger(rateHolder);
// act
// assert
Should.Throw <InvalidCurrencyException>(() => sut.Exchange(exchange));
}
public void Exchange_ShouldReturnTheSameAmount_AsRequested(FxExchange exchange, IExchangeRateHolder rateHolder)
{
// arrange
var sut = new CurrencyExchanger(rateHolder);
exchange.CurrencyPair.From = exchange.CurrencyPair.To;
// act
var result = sut.Exchange(exchange);
// assert
result.ShouldBe(exchange.Amount);
}
private static void ExecuteExchange(FxExchange fxExchange)
{
var exchanger = new CurrencyExchanger(new ExchangeRateHolder(100));
try
{
Console.WriteLine(exchanger.Exchange(fxExchange));
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
public void Exchange_IsCase_Insensitive(string from, string to)
{
// arrange
var exchange = new FxExchange
{
Amount = 1,
CurrencyPair = new CurrencyPair {
From = from, To = to
}
};
var sut = new CurrencyExchanger(new ExchangeRateHolder(100));
// act
// assert
Should.NotThrow(() => sut.Exchange(exchange));
}
public void Exchange_ShouldExchangeTheAmount_AsRequested(string from, string to, int ammount, double expected)
{
// arrange
var exchange = new FxExchange {
Amount = ammount, CurrencyPair = new CurrencyPair {
From = from, To = to
}
};
var sut = new CurrencyExchanger(new ExchangeRateHolder(100));
// act
var result = sut.Exchange(exchange);
// assert
result.ShouldBe(expected);
}
public void Exchange_ShouldThrow_WithMessage(string currency, string expected)
{
// arrange
var exchange = new FxExchange
{
Amount = 1,
CurrencyPair = new CurrencyPair {
From = currency, To = "USD"
}
};
var sut = new CurrencyExchanger(new ExchangeRateHolder(100));
// act
// assert
var exception = Should.Throw <InvalidCurrencyException>(() => sut.Exchange(exchange));
exception.Message.ShouldBe(string.Format(expected, currency));
}
public double Exchange(FxExchange exchange)
{
var currencyPair = exchange.CurrencyPair;
if (currencyPair.From == currencyPair.To)
{
return(exchange.Amount);
}
var hasFrom = _exchangeRateHolder.ExchangeRates.TryGetValue(currencyPair.From.ToUpper(), out var from);
var hasTo = _exchangeRateHolder.ExchangeRates.TryGetValue(currencyPair.To.ToUpper(), out var to);
if (hasFrom && hasTo)
{
return(Math.Round(from * exchange.Amount / to, 4));
}
throw new InvalidCurrencyException(string.Format(Constants.CurrencyNotFound, hasFrom ? currencyPair.To : currencyPair.From));
}