P22 { public static List<Integer> range(int start, int end) { return IntStream.rangeClosed(start, end).boxed().collect(toList()); }  static List<Integer> range(int start, int end);  }
@Test public void shouldCreateARangeBetween4And9() throws Exception { List<Integer> range = P22.range(4, 9); assertThat(range, hasSize(6)); assertThat(range, contains(4, 5, 6, 7, 8, 9)); }