Damage damageComponent = entity.add(Damage.class);
damageComponent.getDamageLevel(Difficulty.EASY).setAmount(40);
assertEquals(40, damageComponent.getDamageLevel(Difficulty.EASY).getAmount());
assertNull(damageComponent.getDamageLevel(null));
assertEquals(0, damageComponent.getDamageLevel(Difficulty.HARD).getAmount());
EntityEffect container = new EntityEffect(EntityEffectType.HASTE, 4);
damageComponent.getDamageLevel(Difficulty.EASY).setEffect(container);
assertEquals(container, damageComponent.getDamageLevel(Difficulty.EASY).getEffect());
assertEquals(null, damageComponent.getDamageLevel(Difficulty.HARD).getEffect());
}