public void RemoveAt_TwoItems_ItemsAreRemovedAndCollectionChangedRaised()
{
var collectionChangedEventArgsList = new List <NotifyCollectionChangedEventArgs>();
var collection = new ExtendedObservableCollection <int> {
135, 123, 456, 789
};
collection.CollectionChanged += (_, args) => collectionChangedEventArgsList.Add(args);
collection.RemoveAt(3);
collection.RemoveAt(1);
Assert.Equal(2, collection.Count);
Assert.Equal(135, collection[0]);
Assert.Equal(456, collection[1]);
Assert.Equal(2, collectionChangedEventArgsList.Count);
Assert.Equal(NotifyCollectionChangedAction.Remove, collectionChangedEventArgsList[0].Action);
Assert.NotNull(collectionChangedEventArgsList[0].OldItems);
Assert.Single(collectionChangedEventArgsList[0].OldItems);
Assert.Equal(789, collectionChangedEventArgsList[0].OldItems[0]);
Assert.Equal(NotifyCollectionChangedAction.Remove, collectionChangedEventArgsList[1].Action);
Assert.NotNull(collectionChangedEventArgsList[1].OldItems);
Assert.Single(collectionChangedEventArgsList[1].OldItems);
Assert.Equal(123, collectionChangedEventArgsList[1].OldItems[0]);
}
