测试出现和消失的动画标签的文本

我正在努力测试标签（toastLabel）的外观，当有人输入错误的电子邮件时，该标签会简短地显示在视图中。

private func registerNewUser(email: String, password: String, confirmationPassword: String) {
    if password == confirmationPassword {
        firebaseData.createUser(email: email, password: password, completion: { (error, _ ) in
            if let error = error {
                self.showToast(in: self.view, with: error.localizedDescription)
            } else {
                self.showToast(in: self.view, with: "Registered succesfully")
                self.signInUser(email: email, password: password)
            }
        })
    } else {
        //raise password mismatch error
        print("password mismatch error")
    }
}

func showToast(in toastSuperView: UIView, with text: String) {
    let toastLabel = ToastLabel()
    toastLabel.text = text
    toastSuperView.addSubview(toastLabel)
    layoutToastLabel(toastLabel)
    animateToastLabel(toastLabel)
}

private func layoutToastLabel(_ toastLabel: ToastLabel) {
    toastLabel.centerYToSuperview()
    toastLabel.pinToSuperview(edges: [.left, .right])
}

private func animateToastLabel(_ toastLabel: ToastLabel) {
    UIView.animate(withDuration: 2.5, delay: 0, options: .curveEaseOut, animations: {
        toastLabel.alpha = 0.0
    }, completion: { _ in
        toastLabel.removeFromSuperview()
    })
}

我只想测试用户输入已接收的电子邮件后，从firebase收到的错误文本是否出现。

func testRegisteringWithUsedEmailDisplaysFirebaseError() {
    let email = registeredEmail
    let password = "password"

    welcomeScreenHelper.register(email: email,
                                 password: password,
                                 confirmationPassword: password,
                                 completion: {

        let firebaseErrorMessage = "The email address is already in use by another account."
        XCTAssert(self.app.staticTexts[firebaseErrorMessage].exists)
    })
}

func register(email: String, password: String, confirmationPassword: String, completion: (() -> Void)? = nil) {
    let emailTextField = app.textFields[AccesID.emailTextField]
    let passwordTextField = app.secureTextFields[AccesID.passwordTextField]
    let confirmPasswordTextField = app.secureTextFields[AccesID.confirmPasswordTextField]
    let registerButton = app.buttons[AccesID.registerButton]

    emailTextField.tap()
    emailTextField.typeText(email)
    passwordTextField.tap()
    passwordTextField.typeText(password)
    registerButton.tap()
    confirmPasswordTextField.tap()
    confirmPasswordTextField.typeText(confirmationPassword)
    registerButton.tap()

    completion?()
}

当我使用期望和XCTWaiter等其他工具时，尽管确实出现了文本和标签，但测试仍未通过。我从来没有做过这样的测试，所以我不确定我要去哪里出错，是否我需要做一些不同的事情来测试动画视图或其他东西。

更新1：

因此，我可以看到经过更多的播放后，当我点击registerButton时，吐司会按原样出现，但直到再次消失后测试才继续。我发现这很奇怪，因为它并没有严格地附加到registerButton本身的视图上。

更新2：

我已经更新了我的测试，如下所示：

func testRegisteringWithUsedEmailDisplaysFirebaseError() {

    welcomeScreenHelper.register(email: registeredEmail,
                                 password: password,
                                 confirmationPassword: password,
                                 completion: {

        let firebaseErrorMessage = "The email address is already in use by another account."

        let text = self.app.staticTexts[firebaseErrorMessage]
        let exists = NSPredicate(format: "exists == true")

        self.expectation(for: exists, evaluatedWith: text, handler: nil)
        self.waitForExpectations(timeout: 10, handler: nil)
        XCTAssert(self.app.staticTexts[firebaseErrorMessage].exists)
    })
}

加上以下内容：

override func setUp() {
    app.launch()
    UIView.setAnimationsEnabled(false)
    super.setUp()
}

override func tearDown() {
    if let email = createdUserEmail {
        firebaseHelper.removeUser(with: email)
    }
    UIView.setAnimationsEnabled(true)
    super.tearDown()
}

但是到目前为止没有运气。我仍然可以看到，func register一旦轻按了注册按钮，就会显示Toast，并且直到toastLabel动画完成后才调用下一行。