public void PredictCurrencyExchangeRate_ValidData_ShouldSucceed(int[] xVals, double[] yVals, int monthToPredict, double expectedValue)
{
// Act
double actualValue = LinearRegression.PredictCurrencyExchangeRate(xVals, yVals, monthToPredict);
// Assert
Assert.Equal(expectedValue, actualValue);
}
public void PredictCurrencyExchangeRate_DifferentArrayLengths_ShouldFail(int[] xVals, double[] yVals, int monthToPredict)
{
// Act
Action act = () => LinearRegression.PredictCurrencyExchangeRate(xVals, yVals, monthToPredict);
// Assert
Assert.Throws <ArgumentException>(act);
}
/// <summary>
/// Predict currency exchange rate based on last year data.
/// </summary>
/// <param name="openExchangeAppID">A valid app ID from Open Exchange Rates</param>
/// <param name="fromCurrency">Currency to exchange from (3-letter code)</param>
/// <param name="toCurrency">Currency to exchange to (3-letter code)</param>
/// <param name="dateToPredict">The date that needs to be predicted.</param>
/// <returns></returns>
public static double PredictCurrencyExchangeRate(string openExchangeAppID, string fromCurrency, string toCurrency, DateTime dateToPredict)
{
// Get last year rates
var oxrHelper = new OpenExchangeRates(openExchangeAppID);
var lastYearRates = oxrHelper.GetYearlyRates(fromCurrency, toCurrency, dateToPredict.AddYears(-1));
// Get predicted value
double predictedValue = LinearRegression.PredictCurrencyExchangeRate(
lastYearRates.Select(r => r.Key).ToArray(), lastYearRates.Select(r => r.Value).ToArray(), dateToPredict.Month);
return(predictedValue);
}