public async Task returns_empty_when_no_currencies_are_found()
{
_messageHandler.Protected()
.Setup <Task <HttpResponseMessage> >(
"SendAsync",
ItExpr.IsAny <HttpRequestMessage>(),
ItExpr.IsAny <CancellationToken>())
.ReturnsAsync(new HttpResponseMessage
{
StatusCode = HttpStatusCode.NotFound
});
var emptyRates = await _retriever.GetAll();
Assert.Empty(emptyRates);
}
private async Task RefreshCache(Currency currencyToRefresh)
{
if (_cache.Count == 0)
{
var newExchangeRates = await _exchangeRatesRetriever.GetAll();
foreach (var(currency, rate) in newExchangeRates)
{
_cache.Add(currency, rate);
}
return;
}
// this can happen when the above method does not load the currency because it was not found
var hasCurrency = _cache.TryGetValue(currencyToRefresh, out var exchangeRate);
if (!hasCurrency)
{
return;
}
var cacheIsFreshFrom = DateTimeOffset.UtcNow.AddDays(-_configuration.CacheRefreshRate).ToUnixTimeSeconds();
var cacheHasExpired = exchangeRate.UpdatedAt < cacheIsFreshFrom;
if (cacheHasExpired)
{
var newExchangeRate = await _exchangeRatesRetriever.Get(currencyToRefresh);
if (newExchangeRate is EmptyExchangeRate)
{
// could not retrieve fresher info
// so its best to remove it and signal this as an issue
// please review the comment in https://github.com/gacastro/rates-r-us#future-improvements
_cache.Remove(currencyToRefresh);
return;
}
_cache[currencyToRefresh] = newExchangeRate;
}
}