Writing test case for static method with linq in moq

Hi , Am new to mock test, am trying to write a test case for the follwing method could shed some light of checking the collection in a simple through mock .And this is static method.

ACollection obj = (ACollection)aCollection.Filter();
var result = aCollection.Where(a => a.IsConditionEvaluatedAndTrue())
.Select(arg =>
new KeyValuePair<int, WebArg>(arg.Key,
new WebArg(arg) { IsConditionTrue = true }))
.OrderByDescending(pair =>
WebArg.MapAllSupportLevelsToNumeric(pair.Value.VerboseArgumentLevel))
.ToDictionary(pair => pair.Key, pair => pair.Value);
return result;