@Test
public void shouldRotateAListByThreeElementsWhenNIs3() throws Exception {

    List<String> rotated = P19.rotate(Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h"), 3);
    assertThat(rotated, equalTo(Arrays.asList("d", "e", "f", "g", "h", "a", "b", "c")));
}