def test_that_board_advances_to_next_state(self):
   game =GameOfLife(10, 10)
   game.set_living_cells([(3,3)])
   game.advance()
   self.assertFalse(game.cell_alive((3,3)))
 def test_can_build_game_of_life_with_initial_state(self):
   game = GameOfLife(10, 10)
   game.set_living_cells([(3,3)])
   self.assertTrue(game.cell_alive((3,3)))