def test_modify_initial_cell(self):
c = Cell(9, 0, 0, 4, is_initial=True)
with self.assertRaises(ValueError):
c.set_possible_value(3)
with self.assertRaises(ValueError):
c.set_value(5)
with self.assertRaises(ValueError):
c.clear_value(6)
with self.assertRaises(ValueError):
c.clear_possible_value(2)
def test_set_value(self):
c = Cell(9, 0, 0)
c2 = c.set_value(0)