public void UpdateUsageTest()
{
string key = "key";
object value = "value";
TimeSpan expiration = TimeSpan.FromSeconds(2);
var cachePolicy = new CachePolicy { SlidingExpiration = expiration };
var cacheItem = new CacheItem(key, value, cachePolicy);
bool hasExpiration = cacheItem.CanExpire();
Assert.AreEqual(true, hasExpiration);
bool isExpired = cacheItem.IsExpired();
Assert.AreEqual(false, isExpired);
Thread.Sleep(TimeSpan.FromSeconds(1));
cacheItem.UpdateUsage();
isExpired = cacheItem.IsExpired();
Assert.AreEqual(false, isExpired);
Thread.Sleep(expiration);
isExpired = cacheItem.IsExpired();
Assert.AreEqual(true, isExpired);
cacheItem.UpdateUsage();
isExpired = cacheItem.IsExpired();
Assert.AreEqual(false, isExpired);
}