public static void ReplaceItemTest()
        {
            string[] anArray = new string[] { "one", "two", "three", "four" };
            ObservableCollection <string>              collection  = new ObservableCollection <string>(anArray);
            ReadOnlyObservableCollection <string>      readonlyCol = new ReadOnlyObservableCollection <string>(collection);
            ReadOnlyCollectionAndPropertyChangedTester helper      = new ReadOnlyCollectionAndPropertyChangedTester();

            helper.ReplaceItemTest(readonlyCol, collection, 1, "seven");
            helper.ReplaceItemTest(readonlyCol, collection, 3, "zero");
        }
 public static void ReplaceItemTest()
 {
     string[] anArray = new string[] { "one", "two", "three", "four" };
     ObservableCollection<string> collection = new ObservableCollection<string>(anArray);
     ReadOnlyObservableCollection<string> readonlyCol = new ReadOnlyObservableCollection<string>(collection);
     ReadOnlyCollectionAndPropertyChangedTester helper = new ReadOnlyCollectionAndPropertyChangedTester();
     helper.ReplaceItemTest(readonlyCol, collection, 1, "seven");
     helper.ReplaceItemTest(readonlyCol, collection, 3, "zero");
 }