How I fix 404 error when test the spring boot using junit with m:m relationship

Question

I am using Spring Boot 3 and have two entities: "Event" and "User". The relationship between these entities is many-to-many. A user can add many events, and an event can have many users.

I created simple Spring Boot endpoints but encountered a 404 error when testing with JUnit on the controller layer. I verified all URL paths and they are correct, but I'm unsure of the issue. The code is as follows: ** Controller layer method** the be test :

@RestController
@RequestMapping("api/users")
@RequiredArgsConstructor
public class UsersController {
    @PutMapping("/{user_id}/{event_id}")
    public ResponseEntity assignUserToEvent(@PathVariable Integer user_id, @PathVariable Integer event_id){
        usersService.assignUserToEvent(user_id,event_id);
        return ResponseEntity.status(200).body("User assigned to event successfully");
    }
}

Service Layer of the method:

@Service
@RequiredArgsConstructor
public class UsersService {
    private final UsersRepository usersRepository;
    private final EventsRepositry eventsRepositry;


    public void assignUserToEvent(Integer user_id, Integer event_id){
        Users users = usersRepository.findUsersById(user_id);
        Events event = eventsRepositry.findEventsById(event_id);

        if (users == null|| event == null)
            throw new ApiException("Sorry can't find the user or event");

        if (!(event.getUsers() ==null)){
            for (int i = 0; i < event.getUsers().size(); i++){ // a user should not be added twice
                if (event.getUsers().get(i).getId() == user_id)
                    throw new ApiException("You already enrolled to this event");
            }
        }

        if (!(users.getEvents()== null)){
            for (int i =0 ; i < users.getEvents().size() ; i++){ // a user should not be added to an event cross with other event
                Events currentEvent = eventsRepositry.findEventsById(users.getEvents().get(i).getId());

                if(event.getDate().isEqual(currentEvent.getDate())){
                    if (event.getStartTime().equals(currentEvent.getStartTime())
                            || (event.getStartTime().isAfter(currentEvent.getStartTime()) && event.getEndTime().isBefore(currentEvent.getEndTime()))
                            || (event.getStartTime().isBefore(currentEvent.getEndTime()) && event.getEndTime().isAfter(currentEvent.getEndTime())
                            || (event.getStartTime().isBefore(currentEvent.getStartTime()) && event.getEndTime().isAfter(currentEvent.getStartTime())) ) )

                        throw new ApiException("You Can't enroll to this event because it conflict with : "+ currentEvent.getName());
                }
            }
        }

        if(event.getDate().isEqual(LocalDate.now()) && event.getStartTime().isBefore(LocalTime.now())) // a user should not be added to an event past it's start time
            throw new ApiException("Sorry you can't enroll to the "+event.getName() +" because it started");


        users.getEvents().add(event);

        usersRepository.save(users);
    }
}

**Model of the user.java, and events.java **both these class have a M:M relationship user.java model

@Entity
@Setter
@Getter
@AllArgsConstructor
@NoArgsConstructor
public class Users {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @Size(min = 2 , max = 20)
    @Column(columnDefinition = "varchar(20)")
    private String name;

    @ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinTable(name = "Events_Users_Table",
    joinColumns = {
            @JoinColumn(name = "user_id",referencedColumnName = "id")
    },
    inverseJoinColumns = {
            @JoinColumn(name = "event_id", referencedColumnName = "id")
    })
    private List<Events> events;
}

**event.java model **

@Entity
@Setter
@Getter
@AllArgsConstructor
@NoArgsConstructor


public class Events {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    private String name;
    private String location;
    private String description;
    private Integer attendees;
    private LocalDate date;
    private LocalTime startTime;
    private LocalTime endTime;

    @ManyToMany(mappedBy = "events",fetch = FetchType.LAZY)
    @JsonIgnore
    private List<Users> users;

}

And the last one is the method that i want test but 404 error appeared

    @Test
    public void assignUserToEventTest() throws Exception {
        mockMvc.perform(put("/api/users/{user_id}/{event_id}",user1.getId(), event1.getId()))
     @AutoConfigureMockMvc(addFilters = false)
@ExtendWith(SpringExtension.class)
@WebMvcTest(value = UsersController.class,excludeAutoConfiguration = {SecurityAutoConfiguration.class})
public class UserControllerTest {

    @MockBean
    UsersService usersService;
    @MockBean
    EventsService eventsService;

    @Autowired
    MockMvc mockMvc;

    Users user1;

    Events event1,event2;
    List<Users> users;

    List<Events> events;

    @BeforeEach
    void setUp(){
        user1 = new Users(null, "Reham Sayer",null);

        event1 = new Events(null, "Event Test 1", "Riyadh", "Event Test Example",3, LocalDate.of(2024,2,20), LocalTime.of(14,00,00),LocalTime.of(16,00,00),null);
        event2 = new Events(null, "Event Test 2", "Riyadh", "Event Test Example",3, LocalDate.of(2024,3,20), LocalTime.of(14,00,00),LocalTime.of(16,00,00),null);
        events = new ArrayList<>();

        events.add(event1);

        users= new ArrayList<>();
        users.add(user1);
    }           .andExpect(status().isOk());
   
    @Test
    public void assignUserToEventTest() throws Exception {
        mockMvc.perform(put("/api/users/{user_id}/{event_id}",user1.getId(), event1.getId()))
                .andExpect(status().isOk());
    }
}

I attempted to change the URL several times and tested it again, but the same issue persisted. Additionally, I believe the problem lies in the relationship between the user and the event, though I cannot confirm this.