public decimal GetConvertedAmount(string fromCountryCode, string toCountryCode, decimal fromAmount)
{
//Could get conversions one time at instantiation, but getting them here assuming they may change
var conversions = _repository.GetConversions();
var fromConversion = conversions.SingleOrDefault(x => x.CurrencyCode.Equals(fromCountryCode, StringComparison.CurrentCultureIgnoreCase));
var toConversion = conversions.SingleOrDefault(x => x.CurrencyCode.Equals(toCountryCode, StringComparison.CurrentCultureIgnoreCase));
if (fromConversion == null)
{
throw new InvalidCurrencyException($"{fromCountryCode} is not a recognized country code.");
}
else if (toConversion == null)
{
throw new InvalidCurrencyException($"{toCountryCode} is not a recognized country code.");
}
if (fromConversion.RateFromUSDToCurrency <= 0)
{
throw new InvalidCurrencyException($"{fromConversion.CurrencyCode} has an invalid rate of {fromConversion.RateFromUSDToCurrency}");
}
else if (toConversion.RateFromUSDToCurrency <= 0)
{
throw new InvalidCurrencyException($"{toConversion.CurrencyCode} has an invalid rate of {toConversion.RateFromUSDToCurrency}");
}
return(fromAmount * (toConversion.RateFromUSDToCurrency / fromConversion.RateFromUSDToCurrency));
}
public void TestAllConversionCombinations()
{
var amount = 1.0M;
var conversions = _repository.GetConversions().ToArray();
var combinations = new List <(string, string)>();
for (int i = 0; i < conversions.Count(); i++)
{
for (int j = i; j < conversions.Count(); j++)
{
combinations.Add((conversions[i].CurrencyCode, conversions[j].CurrencyCode));
}
}
foreach (var combination in combinations)
{
var fromConversion = _repository.GetConversions().SingleOrDefault(x => x.CurrencyCode == combination.Item1);
var toConversion = _repository.GetConversions().SingleOrDefault(x => x.CurrencyCode == combination.Item2);
//Filter out the currencies that I expect to fail. A better way to handle this would be to setup different mock repositories
//for each test case.
if (fromConversion.RateFromUSDToCurrency > 0 && toConversion.RateFromUSDToCurrency > 0 && fromConversion.CurrencyCode != "MAX" && toConversion.CurrencyCode != "MAX")
{
var actualResult = _converter.GetConvertedAmount(combination.Item1, combination.Item2, amount);
var expectedResult = amount * (toConversion.RateFromUSDToCurrency / fromConversion.RateFromUSDToCurrency);
Assert.AreEqual(expectedResult, actualResult, $"{amount}{combination.Item1}->{combination.Item2}");
}
}
}