public void IndexOf_ReturnsMinusOneIfNotInList()
{
VirtualizingList<int> list = new VirtualizingList<int>();
list.UpdateCount(20);
list[2] = 8;
list[10] = 42;
int result = list.IndexOf(15);
Assert.AreEqual(-1, result);
}
public void IndexOf_ReturnsIndexOfItemInList()
{
VirtualizingList<int> list = new VirtualizingList<int>();
list.UpdateCount(20);
list[2] = 8;
list[10] = 42;
int result = list.IndexOf(42);
Assert.AreEqual(10, result);
}