public void ShouldBeAbleToAddToANewCache()
{
var cache = new Cache(10);
cache.Ejector = new RandomEjector(cache);
const string key = "key1";
const string value = "value1";
cache.Add(key, value);
cache.Exists(key).ShouldBeTrue();
}
public void adding_more_items_than_size_should_remove_oldest_item()
{
var cache = new Cache(3);
cache.Ejector = new LRUCacheEjector(cache);
cache.Add("key1", "value1");
cache.Add("key2", "value2");
cache.Add("key3", "value3");
cache.Add("key4","value4");
cache.Exists("key1").ShouldBeFalse("key1 should not be in cache");
cache.Exists("key2").ShouldBeTrue("key2 should be in cache");
cache.Exists("key3").ShouldBeTrue("key3 should be in cache");
cache.Exists("key4").ShouldBeTrue("key4 should be in cache");
}
public void adding_duplicate_keys_should_replace_value()
{
var cache = new Cache(10);
cache.Ejector = new LRUCacheEjector(cache);
string key = "key1";
string value = "value1";
cache.Add(key, value);
cache.Exists(key).ShouldBeTrue();
cache.Get(key).ShouldEqual(value);
value = "some new value";
cache.Add(key,value);
cache.Get(key).ShouldEqual(value);
}
public void AddingDuplicateKeysShouldReplaceValue()
{
var cache = new Cache(10);
cache.Ejector = new RandomEjector(cache);
const string key = "key1";
var value = "value1";
cache.Add(key, value);
cache.Exists(key).ShouldBeTrue();
cache.Get(key).ShouldEqual(value);
value = "some new value";
cache.Add(key, value);
cache.Get(key).ShouldEqual(value);
}
public void get_should_reset_timestamp()
{
var cache = new Cache(3);
cache.Ejector = new LRUCacheEjector(cache);
cache.Add("key1", "value1");
cache.Add("key2", "value2");
cache.Add("key3", "value3");
// if we call Get using key1, it becomes youngest
cache.Get("key1");
// now when we add one more, the oldest should be removed. Oldest is now key2
cache.Add("key4", "value4");
cache.Exists("key1").ShouldBeTrue("key1 should be in cache");
cache.Exists("key2").ShouldBeFalse("key2 should NOT be in cache");
cache.Exists("key3").ShouldBeTrue("key3 should be in cache");
cache.Exists("key4").ShouldBeTrue("key4 should be in cache");
}
public void exists_should_reset_timestamp()
{
var cache = new Cache(3);
cache.Ejector = new LRUCacheEjector(cache);
cache.Add("key1", "value1");
cache.Add("key2", "value2");
cache.Add("key3", "value3");
// if we check whether key1 Exists, it becomes youngest
cache.Exists("key1");
// now when we add one more, the oldest (which is now key2) should be removed.
cache.Add("key4", "value4");
cache.Exists("key1").ShouldBeTrue("key1 should be in cache");
cache.Exists("key2").ShouldBeFalse("key2 should NOT be in cache");
cache.Exists("key3").ShouldBeTrue("key3 should be in cache");
cache.Exists("key4").ShouldBeTrue("key4 should be in cache");
}
public RandomEjector(Cache cache)
{
_cache = cache;
_random = new Random();
}
public void Should_be_able_to_add_to_a_new_cache()
{
var cache = new Cache(10);
cache.Ejector = new LRUCacheEjector(cache);
string key = "key1";
string value = "value1";
cache.Add(key, value);
cache.Exists(key).ShouldBeTrue();
}
private static void RunOneTest(Dictionary<string, int> testResults)
{
var cache = new Cache(3);
cache.Ejector = new RandomEjector(cache);
cache.Add("key1", "value1");
cache.Add("key2", "value2");
cache.Add("key3", "value3");
// the fourth add should cause one of the first three items to be removed. Spec isn't clear
// whether removing a random item could include the item just added. I decided it should not.
cache.Add("key4", "value4");
UpdateTestResults(testResults, cache, "key1");
UpdateTestResults(testResults, cache, "key2");
UpdateTestResults(testResults, cache, "key3");
}
public void YouHaveToInitializeTheEjectionStrategy()
{
var cache = new Cache(10);
cache.Add("key1", "value1");
}
private static void UpdateTestResults(Dictionary<string, int> testResults, Cache cache, string key)
{
if (!cache.Exists(key))
{
testResults[key] += 1;
}
}
