如何在Angular单元测试中建立websocket连接？

import { WebSocketSubject } from 'rxjs/webSocket';

let webSocket: WebSocketSubject<any>;

beforeEach(() => {
  webSocket = new WebSocketSubject<any>('ws://localhost:8080');
});

it('should send and receive messages via WebSocket', () => {
  const messageToSend = { text: 'Hello, WebSocket!' };
  let receivedMessage: any;

  webSocket.subscribe((message) => {
    receivedMessage = message;
  });

  webSocket.next(messageToSend);

  expect(receivedMessage).toEqual(messageToSend);
});