def test_erase_answer_original_number(self):
from sudoku_board import SudokuBox
box = SudokuBox(4)
box.erase_answer()
self.assertEqual(box.answer, 4)
def test_erase_answer(self):
from sudoku_board import SudokuBox
box = SudokuBox()
box.add_answer(4)
box.erase_answer()
self.assertEqual(box.answer, 0)