public void Unique_CreationFunctionWithIndex_CreatesUniqueObject()
{
IEnumerable<int> current = new[] { 1, 2, 3 };
Func<int, int> creationFunc = i => i;
int created = current.CreateUnique(creationFunc);
Assert.AreEqual(4, created);
Assert.IsFalse(current.Contains(created));
}