### Question:
Tileable implements Entity { public Set<TileableListener> getListeners() { return listeners; }  abstract boolean allowsConnection(Direction direction); abstract boolean accepts(Direction direction, Marble marble); abstract void accept(Direction direction, Marble marble); boolean isConnected(Direction direction); boolean isReleasable(Direction direction, Marble marble); void release(Direction direction, Marble marble); Tile getTile(); void setTile(Tile tile); Set<TileableListener> getListeners(); boolean addListener(TileableListener listener); boolean removeListener(TileableListener listener); boolean onGrid();  }### Answer:
@Test public void getListeners() { Tileable tileable = new HorizontalTrack(); assertThat(tileable.getListeners()).isEmpty(); }