在Visual Studio中使用Moq框架在C＃中进行单元测试

嗨，我有这样的代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassLibraryMoq
{
    public class Class1
    {
        public interface ISendr
        {
            string send();
        }

        public class smsSender : ISendr
        {
            public string send()
            {
                return "SMS send";
            }
        }

        public class emailSender : ISendr
        {
            public String send()
            {
                return "Email send";
            }
        }

        public class voiceSend : ISendr
        {
            public string send()
            {
                return "VOICE Send";
            }
        }
        public class sender
        {
            public string send(ISendr obj)
            {
                return obj.send();
            }
        }
    }
}

并在Visual Studio中实现了moq框架，以进行测试，我如何完成它的编译和运行：

using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
using static ClassLibraryMoq.Class1;

namespace UnitTestProject
{
    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void TestMethod1()
        {
            var mock = new Mock<ISendr>();
            var objsender = new sender().send(mock.Object);

        }
    }
}

如何在这里用assert结束测试？谢谢