### Question:
Ack { public static Ack validate(boolean test) { return test ? OK : NOK; }  static Ack validate(boolean test); static Ack validate(Optional<?> optional); static Ack one(int count); Ack and(Ack ack); Ack or(Ack ack); static final Ack OK; static final Ack NOK; }### Answer:
@Test public void validate_true() { assertTrue(Ack.validate(true).isSuccess()); }
@Test public void validate_false() { assertFalse(Ack.validate(false).isSuccess()); }