Spring How to write Junit4 about Websocket

I know how to test websocket, like use WebSocketKing or Postman(2021/5/20), and it works good

I have no idea about writing websocket in unit test

usually, I use "SpringJUnit4ClassRunner" and "@WebAppConfiguration" to mock my service and test my controller

but how to create a mock websocket server to test my websocket in unit test?

Can I use the way like my SimpleControllerTest to create a mock webSocket server?

if I can , How to do it?

and sorry about my bad English , thanks all

Environmen
Java : 1.8
Server : Tomcat 8.5
Test : Junit 4
Socket : javax.websocket.jar
Framework : Spring MVC

My Simple WebSocket Code

package com.ws.socket;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;

@ServerEndpoint(value = "/MyEndpoint")
public class Socket {

    private SocketConnection socketConnection;

    @OnOpen
    public void onOpen(Session session) {
        socketConnection = new SocketConnectionImpl(session);
        socketConnection.onOpen(session.getId());
    }

    @OnClose
    public void onClose(Session session) {
        socketConnection.onClose(session.getId());
    }

    @OnMessage
    public void onMessage(Session session, String msg) throws IOException {
        socketConnection.onMessage(session, msg);
    }

    @OnError
    public void onError(Session session, Throwable error) {
        socketConnection.onError(session.getId(), error);
    }
}

public abstract class SocketConnection {

    protected SocketConnection(Session session) {
    }

    protected void onOpen(String sessionId) {
        System.out.println(sessionId + " build websocket connection !");
    }

    protected void onClose(String sessionId) {
        System.out.println(sessionId + " close connection !");
    }

    protected void onMessage(Session session, String msg) throws IOException {
        System.out.println(session.getId() + " say : " + msg);
        session.getBasicRemote().sendText(" already receive msg about your say " + msg);
    }

    protected void onError(String sessionId, Throwable error) {
        System.out.println(sessionId + " get error , message = " + error.getMessage());
    }
}

My Simple Test Controller

package com.ws.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class SimpleController {

    @GetMapping("/test")
    public String testService() {
        return "start success!";
    }
}

My Simple Controller Test

package com.ws.controller;

import com.ws.config.ServletConfig;
import com.ws.config.SpringConfig;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;

@WebAppConfiguration
@ContextConfiguration(classes = {ServletConfig.class, SpringConfig.class})
@RunWith(SpringJUnit4ClassRunner.class)
public class SimpleControllerTest {
    @Autowired
    WebApplicationContext webApplicationContext;

    MockMvc mvc;

    @Before
    public void init() {
        mvc = MockMvcBuilders.webAppContextSetup(webApplicationContext)
                .build();
    }

    @Test
    public void testAPI() throws Exception {
        String result = mvc.perform(get("/test")).andReturn().getResponse().getContentAsString();
        Assert.assertEquals("start success!", result);
    }
}