public async Task GetCurrencyLiveRates_InvokeExpectedMethod()
{
var provider = new Mock <IExchangeRateProvider>();
provider.Setup(c => c.SystemName).Returns("sysname");
_settings.ActiveExchangeRateProviderSystemName = "sysname";
var exchangeRateService = new ExchangeRateService(new List <IExchangeRateProvider>()
{
provider.Object
}, _settings);
await exchangeRateService.GetCurrencyLiveRates("rate");
provider.Verify(c => c.GetCurrencyLiveRates(It.IsAny <string>()), Times.Once);
}