Swift 表视图插座单元测试失败

我正在使用故事板，并且在视图控制器中创建了出口.在视图加载中，我已经将委托和数据源设置为self.我试图为表视图出口编写单元测试，但实际上，它返回nil，尽管它存在..

以下是视图模型代码.

class CakeListViewModel: CakeListViewModelType {
    

    weak private var delegate: CakeListViewType!
    let service:Service!
    
    private var cakes:[Cake]?
    
    var itemCount: Int {
        return cakes?.count ?? 0
    }
    
    init(delegate: CakeListViewType,
         service:Service = ServiceImpl()) {
        self.delegate = delegate
        self.service = service
    }
    
    /*
     this method connect calls rest API to get data
     */
    func fetchCakes() {
        let client = ServiceClient(baseUrl:EndPoints.baseUrl.rawValue, path:Path.cakeList.rawValue, params:"", method:"get")
        
        service.fetchData(client:client, type:Cake.self) { [weak self] (result)  in
            switch result {
            case .success(let result):
                self?.cakes = result
                DispatchQueue.main.async {
                    self?.delegate?.updateUI()
                }
            case .failure(_):
                self?.cakes = nil
                DispatchQueue.main.async {
                    self?.delegate?.showError()
                }
            }
        }
    }
}

这是我的测试代码..

class CakeViewModelTest: XCTestCase {
    
    var mockService:MockService!
    var viewModel:CakeListViewModel!


    override func setUp() {
        mockService = MockService()
        let vc = CakeListViewController()
        viewModel = CakeListViewModel(delegate:vc, service:mockService)
    }

    func testTableViewOutlet() {
        let vc =  CakeListViewController()
        XCTAssertNotNil(vc.tableView)
    }
}

以下是我的视图控制器代码.

class CakeListViewController: UIViewController {
    
    @IBOutlet var tableView: UITableView!
    
    var viewModel:CakeListViewModelType!
    weak var coordinator: Coordinator?

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        tableView.delegate = self
        title = "?CakeItApp?"
        
        viewModel.fetchCakes()
    }
}

以下是错误的屏幕截图.