[Test]
    // LFU: Least Frequently Used
    public void Test_BasicLFUCacheSemantic()
    {
        var lfuCache = new MemoryCache<int, string>();
        lfuCache.SetPolicy(typeof(LfuEvictionPolicy<,>));
        
        // Note the default number of ways is 1, and the default capacity is 16...
        Assert.AreEqual(lfuCache.Capacity, AbstractCache.DefaultCapacity);

        var data =
            Enumerable.Range(0, AbstractCache.DefaultCapacity + 1).
            Aggregate(new StringBuilder(), (sb, i) => sb.Append(i > 0 ? String.Format(",String {0}", i) : String.Empty)).
            ToString().
            Split(',');

        // Cache all the (16) non-empty strings
        for (var i = 1; i < data.Length; i++)
        {
            lfuCache.Add(i, data[i]);
        }

        // Use all the (16) non-empty strings four times...
        for (var use = 1; use <= 4; use++)
        {
            for (var i = 1; i < data.Length; i++)
            {
                // ... except for "String 3", used only twice...
                if (i == 3)
                {
                    if (use <= 2)
                    {
                        var s = lfuCache.Get(i);
                    }
                }
                // ... and for "String 9", used only once
                else if (i == 9)
                {
                    if (use <= 1)
                    {
                        var s = lfuCache.Get(i);
                    }
                }
                else
                {
                    var s = lfuCache.Get(i);
                }
            }
        }

        lfuCache.Add(17, "String 17");
        Assert.AreEqual(lfuCache.Contains(9), false);
        Assert.AreEqual(lfuCache.Contains(17), true);

        var used4times = lfuCache.Get(17);
        used4times = lfuCache.Get(17);
        used4times = lfuCache.Get(17);
        used4times = lfuCache.Get(17);

        lfuCache.Put(18, "String 18");
        Assert.AreEqual(lfuCache.Contains(3), false);
        Assert.AreEqual(lfuCache.Contains(17), true);
        Assert.AreEqual(lfuCache.Contains(18), true);
    }