Почему @WebSocketServer() private server: Server является null?

Question

[linoa123]

import { Module } from '@nestjs/common';
import { TestService } from './test.service';
import { TestGateway } from './test.gateway';

@Module({
  providers: [TestGateway, TestService],
})
export class TestModule {}

import { WebSocketGateway, SubscribeMessage, MessageBody } from '@nestjs/websockets';
import { TestService } from './test.service';
import { CreateTestDto } from './dto/create-test.dto';
import { UpdateTestDto } from './dto/update-test.dto';

@WebSocketGateway(3002, {
  cors: {
    origin: process.env.CLIENT_URL,
    methods: ["GET", "POST"],
    allowedHeaders: ["Content-Type"],
    credentials: true,
  },
  namespace: '/'
})export class TestGateway {
  constructor(private readonly testService: TestService) {}

  @SubscribeMessage('createTest')
  create(@MessageBody() createTestDto: CreateTestDto) {
    return this.testService.create(createTestDto);
  }

  @SubscribeMessage('findAllTest')
  findAll() {
    return this.testService.findAll();
  }

  @SubscribeMessage('findOneTest')
  findOne(@MessageBody() id: number) {
    return this.testService.findOne(id);
  }

  @SubscribeMessage('updateTest')
  update(@MessageBody() updateTestDto: UpdateTestDto) {
    return this.testService.update(updateTestDto.id, updateTestDto);
  }

  @SubscribeMessage('removeTest')
  remove(@MessageBody() id: number) {
    return this.testService.remove(id);
  }
}

import { Injectable } from '@nestjs/common';
import { CreateTestDto } from './dto/create-test.dto';
import { UpdateTestDto } from './dto/update-test.dto';
import { WebSocketServer } from '@nestjs/websockets';
import { Server } from 'socket.io';

@Injectable()
export class TestService {
  @WebSocketServer() 
  private server: Server;

  create(createTestDto: CreateTestDto) {
    return 'This action adds a new test';
  }

  findAll() {
    return this.server.emit('findAllTest', { body: 'hello' });
  }

  findOne(id: number) {
    return `This action returns a #${id} test`;
  }

  update(id: number, updateTestDto: UpdateTestDto) {
    return `This action updates a #${id} test`;
  }

  remove(id: number) {
    return `This action removes a #${id} test`;
  }
}