feat: notify authors when admin deletes post

backend/src/test/java/com/openisle/service/PostServiceTest.java

@@ -61,6 +61,58 @@ class PostServiceTest {
         verify(postRepo).delete(post);
     }
 
+    @Test
+    void deletePostByAdminNotifiesAuthor() {
+        PostRepository postRepo = mock(PostRepository.class);
+        UserRepository userRepo = mock(UserRepository.class);
+        CategoryRepository catRepo = mock(CategoryRepository.class);
+        TagRepository tagRepo = mock(TagRepository.class);
+        LotteryPostRepository lotteryRepo = mock(LotteryPostRepository.class);
+        NotificationService notifService = mock(NotificationService.class);
+        SubscriptionService subService = mock(SubscriptionService.class);
+        CommentService commentService = mock(CommentService.class);
+        CommentRepository commentRepo = mock(CommentRepository.class);
+        ReactionRepository reactionRepo = mock(ReactionRepository.class);
+        PostSubscriptionRepository subRepo = mock(PostSubscriptionRepository.class);
+        NotificationRepository notificationRepo = mock(NotificationRepository.class);
+        PostReadService postReadService = mock(PostReadService.class);
+        ImageUploader imageUploader = mock(ImageUploader.class);
+        TaskScheduler taskScheduler = mock(TaskScheduler.class);
+        EmailSender emailSender = mock(EmailSender.class);
+        ApplicationContext context = mock(ApplicationContext.class);
+
+        PostService service = new PostService(postRepo, userRepo, catRepo, tagRepo, lotteryRepo,
+                notifService, subService, commentService, commentRepo,
+                reactionRepo, subRepo, notificationRepo, postReadService,
+                imageUploader, taskScheduler, emailSender, context, PublishMode.DIRECT);
+        when(context.getBean(PostService.class)).thenReturn(service);
+
+        Post post = new Post();
+        post.setId(1L);
+        post.setTitle("T");
+        post.setContent("");
+        User author = new User();
+        author.setId(2L);
+        author.setRole(Role.USER);
+        post.setAuthor(author);
+
+        User admin = new User();
+        admin.setId(1L);
+        admin.setRole(Role.ADMIN);
+
+        when(postRepo.findById(1L)).thenReturn(Optional.of(post));
+        when(userRepo.findByUsername("admin")).thenReturn(Optional.of(admin));
+        when(commentRepo.findByPostAndParentIsNullOrderByCreatedAtAsc(post)).thenReturn(List.of());
+        when(reactionRepo.findByPost(post)).thenReturn(List.of());
+        when(subRepo.findByPost(post)).thenReturn(List.of());
+        when(notificationRepo.findByPost(post)).thenReturn(List.of());
+
+        service.deletePost(1L, "admin");
+
+        verify(notifService).createNotification(eq(author), eq(NotificationType.POST_DELETED), isNull(),
+                isNull(), isNull(), eq(admin), isNull(), eq("T"));
+    }
+
     @Test
     void createPostRespectsRateLimit() {
         PostRepository postRepo = mock(PostRepository.class);