public void Set_AddToExisting() { string cacheKey = "Set_AddToExisting"; handler.Remove(cacheKey); List <int> items = new List <int>() { 1, 2, 3, 4, 5 }; HashSet <int> set = new HashSet <int>(items); handler.Register(cacheKey, new Func <ISet <int> >(() => set), TimeSpan.FromMinutes(30)); handler.SetAdd(cacheKey, 6); if (handler.CacheEnabled) { var exists = handler.SetExists(cacheKey, 6); Assert.AreEqual(true, exists); } handler.Remove(cacheKey); }