@Test
    public void testEquals() {
        SudokuBoard sb1 = new SudokuBoard();
        SudokuBoard sb2 = new SudokuBoard();

        assertTrue(sb1.equals(sb2) && sb2.equals(sb1) );
        assertTrue(sb1.hashCode() == sb2.hashCode());
    }


 @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof SudokuBoard)) return false;
        SudokuBoard other = (SudokuBoard) o;
        return Objects.equal(tmpFields, other.tmpFields);
    }