C＃模拟一个函数

Question

我需要从谷歌日历api模拟一个方法。但它每次都会出错。我有以下代码。

        DateTime dateTimeNow = new DateTime(2018, 10, 10, 10, 10, 10);
        Event events = new Event
        {
            Id = "EventA",
            Summary = "Summary",
            Description = "Desc",
            Start = new EventDateTime { Date = "2018-10-10", DateTime = dateTimeNow},
            End = new EventDateTime { Date = "2018-10-10", DateTime = dateTimeNow.AddHours(1) },
        };

        Mock<CalendarService> fakeCalendarService = new Mock<CalendarService>();
        fakeCalendarService
            .Setup(x => x.Events.Insert(It.IsAny<Event>(), It.IsAny<string>()).Execute())
            .Returns(events);

我收到以下错误消息：

Message: System.NotSupportedException : Invalid setup on a non-virtual (overridable in VB) member: x => x.Events.Insert(It.IsAny<Event>(), It.IsAny<String>()).Execute()

我能够模拟其他功能但是这个功能：

_service.Events.Insert(newEvent, _calendarId).Execute();

后面有.Execute（）。由于这个陈述，我不知道如何嘲笑它。