### Question:
DataSet { public Movie getMovieById(long id) { for (int i = 0; i < movieList.size(); i++) { if (movieList.get(i).getId() == id) { return movieList.get(i); } } return null; } DataSet(DateFormat dateFormat); List<IUser> getUserList(); IUser getUserById(int id); IUser getUserByName(String name); void updateRentalsWithUser(User user); Object[][] getUserListAsObject(); List<Movie> getMovieList(); Object[][] getMovieListAsObject(boolean rented, boolean available); Movie getMovieById(long id); void updateMovie(Movie movie); Object[][] getMovieListAsObject(); List<Rental> getRentalList(); Object[][] getRentalListAsObject(); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void testGetMovieById() { Movie m = ds.getMovieById(1); assertNotNull(m); assertEquals(1, m.getId()); m = ds.getMovieById(-1000); assertNull(m); }