@Test
    public void test_toString(){
        assertNotNull(board);
        board.removeAllPawns();

        Pawn pawn1 = new Pawn('l', 2,2, board);
        board.addPawn(pawn1);

        Pawn pawn2 = new Pawn('m', 2,1, board);
        board.addPawn(pawn2);
        assertNotNull(board.toString());

    }