public async Task DeleteAllRemovesCache()
        {
            AutoCacheOptions.SaveCollections = true;
            AutoCacheOptions.AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(10);
            _autoCache = new CrudAutoCache <string, Guid>(_storage, item => ToGuid(item, 1), Cache, null, AutoCacheOptions);
            var id1 = ToGuid("A1", 1);

            await PrepareStorageAndCacheAsync(id1, "A1", null);

            var id2 = ToGuid("B1", 1);

            await PrepareStorageAndCacheAsync(id2, "B1", null);

            await _autoCache.ReadAllAsync();

            await _autoCache.DeleteAllAsync();

            var result = await _autoCache.ReadAllAsync();

            Assert.IsNotNull(result);
            var enumerable = result as string[] ?? result.ToArray();

            Assert.AreEqual(0, enumerable.Length);
        }