public static void testPickNext() {
List<Integer> list = new ArrayList<>(10);
for (int i = 0; i < 10; i++) list.add(i);
Integer num = Util.pickNext(list, 5);
System.out.println("number next to 5: " + num);
assert num != null;
assert num.equals(6);
num = Util.pickNext(list, 9);
System.out.println("number next to 9: " + num);
assert num != null;
assert num.equals(0);
num = Util.pickNext(list, 11);
assert num == null;
}
public static void testPickNextN() {
List<Integer> list = Arrays.asList(1, 2, 3, 4);
List<Integer> result = Util.pickNext(list, 0, 1);
assert result.isEmpty();
result = Util.pickNext(list, 1, 1);
System.out.println("result = " + result);
assert result.size() == 1;
assert result.contains(2);
result = Util.pickNext(list, 3, 2);
System.out.println("result = " + result);
assert result.size() == 2;
assert result.contains(4) && result.contains(1);
result = Util.pickNext(list, 4, 5);
System.out.println("result = " + result);
assert result.size() == 3;
assert result.contains(1) && result.contains(2) && result.contains(3);
}