@Test
 public void testIsOccupied() throws StrategyException {
   Position pos = new Position(0, 0);
   assertFalse(board.isOccupied(pos));
   board.putPieceAt(pos, new Piece(PieceType.BOMB, PlayerColor.RED));
   assertTrue(board.isOccupied(pos));
   board.putPieceAt(pos, Piece.WATER_PIECE);
   assertFalse(board.isOccupied(pos));
 }
 @Test(expected = ArrayIndexOutOfBoundsException.class)
 public void testIsOccupiedInvalidPosition() {
   board.isOccupied(new Position(-1, 0));
 }