Есть ли опыт работы с Unit тестами

@Test
public void testAddUser() {
    UserService userService = new UserService();
    User user = new User("test@example.com");
    
    User savedUser = userService.addUser(user);
    
    assertNotNull(savedUser.getId());
    assertEquals("test@example.com", savedUser.getEmail());
}

@Test
public void testGetUserById() {
    UserRepository mockRepo = mock(UserRepository.class);
    when(mockRepo.findById(1L)).thenReturn(Optional.of(new User(1L, "test@example.com")));
    
    UserService service = new UserService(mockRepo);
    User user = service.getUserById(1L);
    
    assertEquals(1L, user.getId());
}