@Test
public void replace(){
Mask mask = new MaskImpl(
new Slot[]{
new Slot(Slot.RULE_INPUT_REPLACE, '1', SlotValidatorSet.setOf(new SlotValidators.GenerousValidator())),
new Slot(Slot.RULE_INPUT_REPLACE, '2', SlotValidatorSet.setOf(new SlotValidators.GenerousValidator())),
new Slot(Slot.RULE_INPUT_REPLACE, '3', SlotValidatorSet.setOf(new SlotValidators.GenerousValidator())),
new Slot(Slot.RULE_INPUT_REPLACE, null, SlotValidatorSet.setOf(new SlotValidators.GenerousValidator()))
}, true
);
assertEquals("123", mask.toString());
assertEquals(1,mask.insertFront("0"));
assertEquals(2,mask.insertAt(1, "1"));
assertEquals("013", mask.toString());
}