public void on_addition_should_fire_when_a_cache_adds_something_from_its_on_missing_catch()
{
var list = new List<int>();
int x = 0;
cache.OnMissing = key => ++x;
cache.OnAddition = number => list.Add(number);
cache["a"] = 100;
cache["b"].ShouldBe(1);
cache["c"].ShouldBe(2);
list.ShouldHaveTheSameElementsAs(100, 1, 2);
}