refactoring uitesing.swift

    func test_should_display_error_message_for_missing_required_fields() {

        let app = XCUIApplication()
        continueAfterFailure = false
        let loginPageObject = LoginPageObject(app: app)
        app.launch()
        
        let usernameTextField = loginPageObject.usernameTextField
        usernameTextField.tap()
        usernameTextField.typeText("")

        let passwordTextField = loginPageObject.passwordTextField
        passwordTextField.tap()
        passwordTextField.typeText("")

        let loginButton = loginPageObject.loginButton
        loginButton.tap()

        let messageText = loginPageObject.messageText
        XCTAssertEqual(messageText.label, "Required fields are missing")
    }