尝试在iOS中对segue进行单元测试，测试总是失败

Question

我正在尝试为segue编写单元测试。我的代码看起来像

private var sut: PresentViewController!
    // sut is System Under Test
    override func setUp() {
        super.setUp()
        let storyboard = UIStoryboard(name: "Research", bundle: Bundle.main)
        let rootVC = storyboard.instantiateInitialViewController() as? UINavigationController
        self.sut = rootVC?.viewControllers.first as? PresentViewController
        let window = UIWindow(frame: UIScreen.main.bounds)
        window.rootViewController = self.sut
        window.makeKeyAndVisible()
        sut.loadViewIfNeeded()
    }

func testHelpButtonPresentViewController() {
        XCTAssertNil(sut.presentedViewController)
        UIApplication.shared.keyWindow?.rootViewController = self.sut
        self.sut.performSegue(withIdentifier: "showInfoViewController", sender: nil)
        XCTAssertNotNil(sut.navigationController)
        XCTAssertTrue(sut.navigationController?.presentedViewController is DestinationViewController)
    }

获得以下错误 警告：尝试出席＆lt; UINavigationController：0x7f845f84c000＆gt; on＆lt; myScheme.CurrentViewController：0x7f845e7108f0＆gt;其视图不在窗口层次结构中！

segue由按钮操作

触发

种类：以模态呈现

演示文稿：来自表格

我的故事板如下：