TweetService { public void delete(String id) { tweetsDatabase.remove(id); System.out.println("Tweet deleted successfully. Remained tweets: " + tweetsDatabase); }  void save(Tweet tweet); void delete(String id); Tweet findById(String id); int size(); List<Tweet> findAll(); List<Tweet> search(String someString);  }
@Test public void deleteTest() { tweetService.delete(tweet1.getId()); assertEquals(0, tweetService.size()); }