How can i test the nestjs-graphql resolver with guard?

Question

This is a sample code of resolver and i want to test this with the jest on nestJS.

@Resolver()
export class UserResolver {
  constructor(private readonly userService: UserService) {}

  @UseGuards(GqlAccessGuard)
  @Query(() => User)
  async fetchUser(@CurrentUser() currentUser: ICurrentUser) {
    return this.userService.findUserById({ id: currentUser.id });
  }

  @Mutation(() => User)
  async createUser(@Args('createUserInput') createUserInput: CreateUserInput) {
    return this.userService.create(createUserInput);
  }
}

When I'm trying to test the "fetchUser" api of this resolver I'm stucked with the @UseGuard(). I don't know how can i import or provide the 'GQlAccessGuard' into the test code. Since I use the NestJs to build Graphql-codefirst server I used custom guard that extends AuthGuards to convert Context that request has.

export class GqlAccessGuard extends AuthGuard('access') {
  getRequest(context: ExecutionContext) {
    const ctx = GqlExecutionContext.create(context);
    return ctx.getContext().req;
  }
}

@Injectable()
export class JwtAccessStrategy extends PassportStrategy(Strategy, 'access') {
  constructor() {
    super({
      jwtFromRequest: ExtractJwt.fromAuthHeaderAsBearerToken(),
      ignoreExpiration: false,
      secretOrKey: 'jwt-access-token-key',
    });
  }

  async validate(payload: any) {
    return {
      id: payload.sub,
      email: payload.email,
      role: payload.role,
    };
  }
}

const createUserInput: CreateUserInput = {
  email: '[email protected]',
  name: 'test',
  password: 'testpwd',
  phone: '010-1234-5678',
  role: Role.USER,
};

class MockGqlGuard extends AuthGuard('access') {
  getRequest(context: ExecutionContext) {
    const ctx = GqlExecutionContext.create(context);
    return ctx.getContext().req;
  }
}

describe('UserResolver', () => {
  let userResolver: UserResolver;

  beforeEach(async () => {
    const moduleRef = await Test.createTestingModule({
      imports: [JwtModule.register({})],
      providers: [UserResolver, JwtAccessStrategy],
    })
      .useMocker((token) => {
        if (token === UserService) {
          return {
            create: jest.fn().mockReturnValue({
              id: 'testuuid',
              email: '[email protected]',
              name: 'test',
              password: 'testpwd',
              phone: '010-1234-5678',
              role: Role.USER,
            }),
          };
        }
      })
      .overrideGuard(GqlAccessGuard)
      .useValue(MockGqlGuard)
      .compile();

    userResolver = moduleRef.get<UserResolver>(UserResolver);
  });

  describe('create', () => {
    it('should return user created', async () => {
      const result: User = {
        id: 'testuuid',
        email: '[email protected]',
        name: 'test',
        password: 'testpwd',
        phone: '010-1234-5678',
        role: Role.USER,
      };

      expect(await userResolver.createUser(createUserInput)).toStrictEqual(
        result,
      );
    });
  });
});

I'm so curious about this and spent several days to search about it. also want to know how can i deal with the customized decorator(createParamDecorator that i made) to use on the test code. please help me on this and provide me with some references.