public void adding_an_item_updates_the_personal_best_count()
{
var model = new PostedTimeCollectionModel();
var observer = model.CreateObserver();
model.Add(PT(15, PostedTimeType.PersonalBest, 1));
Assert.Equal(1, model.PersonalBestCount);
Assert.True(observer.HasChanged(x => x.PersonalBestCount));
}