public void CanMergeEmptyUsages()
{
var period = new QueryTimePeriod(DateTimeOffset.Now, DateTimeOffset.Now);
var usage1 = new Cost(period, new UsageResponse(new UsageResponseProperties(new List <Column>(), new List <List <object> >()), null));
var usage2 = new Cost(period, new UsageResponse(new UsageResponseProperties(new List <Column>(), new List <List <object> >()), null));
Assert.NotNull(Cost.Aggregate(usage1, usage2));
Assert.NotNull(Cost.Aggregate(usage2, usage1));
}