### Question:
CollidableModel extends FeatureModel implements Collidable, Recyclable, TransformableListener, IdentifiableListener { @Override public void notifyCollided(Collidable collidable, Collision with, Collision by) { for (int i = 0; i < listenable.size(); i++) { listenable.get(i).notifyCollided(collidable, with, by); } } CollidableModel(Services services, Setup setup); @Override void prepare(FeatureProvider provider); @Override void checkListener(Object listener); @Override void addListener(CollidableListener listener); @Override void removeListener(CollidableListener listener); @Override void addCollision(Collision collision); @Override void addAccept(Integer group); @Override void removeAccept(Integer group); @Override void forceUpdate(); @Override List<CollisionCouple> collide(Collidable other); @Override void render(Graphic g); @Override void setGroup(Integer group); @Override void setOrigin(Origin origin); @Override void setEnabled(boolean enabled, Collision collision); @Override void setEnabled(boolean enabled); @Override void setCollisionVisibility(boolean visible); @Override boolean isEnabled(); @Override List<Collision> getCollisions(); @Override List<Rectangle> getCollisionBounds(); @Override void notifyCollided(Collidable collidable, Collision with, Collision by); @Override Integer getGroup(); @Override Collection<Integer> getAccepted(); @Override int getMaxWidth(); @Override int getMaxHeight(); @Override Origin getOrigin(); @Override void recycle(); @Override void notifyTransformed(Transformable transformable); @Override void notifyDestroyed(Integer id); @Override boolean isEnabled(Collision collision);  }### Answer:
@Test void testListenerVoid() { assertNotNull(CollidableListenerVoid.getInstance()); CollidableListenerVoid.getInstance().notifyCollided(null, null, null); }