public async Task TestExchangeEURtoCOP(decimal value, string fromCurrency, string targetCurrency)
{
string url = @"http://data.fixer.io/api/latest?access_key=d0def2e2f997f931537d524b82434b2d&symbols=EUR,USD,COP";
ExchangeManager exchange = new ExchangeManager(url);
decimal result = await exchange.ExchangeCurrencies(value, fromCurrency, targetCurrency);
Assert.GreaterOrEqual(result, 0);
}