### Question:
Tileable implements Entity { public void release(Direction direction, Marble marble) { if (tile == null) { throw new IllegalStateException(TILEABLE_UNPLACED); } Tile neighbour = tile.get(direction); if (neighbour != null) { informRelease(direction, marble); neighbour.getTileable().accept(direction.inverse(), marble); } }  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 unplacedRelease() { Track track = new HorizontalTrack(); assertThatThrownBy(() -> track.release(Direction.RIGHT, new Marble(MarbleType.BLUE))) .isInstanceOf(IllegalStateException.class); }