### Question:
SudokuBoardManager implements Serializable { long getDuration() { return this.duration; } SudokuBoardManager(User user, int numMissingDigit); User getUser();  }### Answer:
@Test public void testGetDuration() { SudokuBoardManager bm = new SudokuBoardManager(user, 81); long duration = 0; assertEquals(duration, bm.getDuration()); }