public void CopyTo_GivenASufficienlySizedArrayAndAnIndexOf2_ShouldCopyTheKeysInTheSkiplistToTheArrayInOrderFromIndex2
            (Skiplist <int> sut, List <int> keys)
        {
            // Fixture setup
            var expectedResult = new[] { 0, 0, 0 }.Concat(keys.OrderBy(x => x)).ToArray();

            // Exercise system
            var result = new int[expectedResult.Count()];

            sut.CopyTo(result, 3);

            // Verify outcome
            Assert.Equal(expectedResult, result);

            // Teardown
        }