c# - 如何通过实现接口(interface)来模拟TCPClient

Question

我是计算机科学的新手，对网络知识了解不多。我在实习期间接到了一个任务，就是通过实现接口(interface)来模拟一个TCPClient。这个想法是因为我们不需要连接到真实的服务器，我们只需要一个模拟的 TCPClient 来接收数据，保存并发送出去。据我了解，是否只是模拟TCPClient中的sendmessage函数？？

public interface ITCPClient
{
    /// <summary>
    /// Event handler when TCP client is connected 
    /// </summary>
    event ConnectionEventHandler Connected;

    /// <summary>
    /// Event handler for TCP Client on receiving data
    /// </summary>
    event DataReceivedEventHandler DataReceived;

    /// <summary>
    /// Event handler when TCP client is disconnect
    /// </summary>
    event ConnectionEventHandler Disconnected;

    /// <summary>
    /// Reports error when an error occurs
    /// </summary>
    event ErrorEventHandler OnError;

    /// <summary>
    /// Set whether to use HostByteOrder or NetworkByteorder with the socket - gateway expects network byte order
    /// </summary>
    bool ByteOrder { get; set; }

    /// <summary>
    /// Returns true if the client is running and connected to the server
    /// </summary>
    bool IsRunning { get; }

    /// <summary>
    /// Add the message to the sendqueue. The message will be processed by the ProcessMessage function waiting for the message.
    /// </summary>
    /// <param name="Message"></param>
    void SendMessage(string Message);

    /// <summary>
    /// Add the message to the sendqueue. The message willbe processed by the ProcessMessage function waiting for the message.
    /// </summary>
    /// <param name="Message"></param>
    void SendMessageHiPriority(string Message);

    /// <summary>
    /// Starts the client and spawn the thread for processing the message
    /// </summary>
    void Start();

    /// <summary>
    /// Disconnects and stops listening for messages 
    /// </summary>
    void StopProcessing();

}

public class MockTCPClient : ITCPClient
{
    #region Private Fields

    private string msg;

    #endregion Private Fields


    #region Constructor

    public MockTCPClient()
    {
        //nothing 
    }


    #endregion Constructor

    #region event

    public event ConnectionEventHandler Connected;
    public event ConnectionEventHandler Disconnected;
    public event ErrorEventHandler OnError;
    public event DataReceivedEventHandler DataReceived;

    #endregion event 

    #region property
    //question 
    public string ReceivedMessage
    {
        get
        {
            return msg;
        }

        set
        {
            msg = value;
        }

    }

    #endregion property

    //question??
    private void OnDataReceived(object sender, string e)
    {
        DataReceivedEventHandler dataReceived = DataReceived;
        if (dataReceived != null)
            dataReceived(this, e);
    }


    #region ITCPClient Members
    #region properties

    public bool ByteOrder { get; set; }


    public bool IsRunning { get; }

    #endregion properties

    public void SendMessage(string Message)
    {
        msg = Message;
    }

    public void SendMessageHiPriority(string Message)
    {    
    }

    public void Start()
    {
    }


    public void StopProcessing()
    {
    }


    #endregion ITCPClient Members

}

Answer 1

这演示了 Moq 如何验证您的类是否调用了它的方法之一。

这个测试
- 创建 ITCPClient 的模拟
- 指定 SendMessage 方法是可验证的 - 换句话说，它的使用将被跟踪。
- 验证是否已在模拟对象上调用了 SendMessage("test");。

测试将失败，因为它从不调用 SendMessage("test");

[TestMethod]
public void TestTcpClient()
{
    var mockedTcpClient = new Mock<ITCPClient>();
    mockedTcpClient.Setup(x => x.SendMessage(It.IsAny<string>())).Verifiable();
    //mockedTcpClient.Object.SendMessage("test");
    mockedTcpClient.Verify(x=>x.SendMessage("test"));
}

如果我们取消注释调用 SendMessage("test") 的行，那么测试将通过。

因此在“实际”使用中，您将创建 Mock 并在测试依赖于它的类时使用它代替 ITCPClient。完成后，您可以验证您的类调用了 SendMessage 并传递了预期值。

如果您不能使用 Moq，这里有一个完全不同的方法:

创建一个实现 ITCPClient 的类，如下所示。您可以将大部分方法留空，只实现 SendMessage 以及其他一些细节:

public class TcpClientMock : ITCPClient
{
    private readonly List<string> _sentMessages;

    public TcpClientMock(List<string> sentMessages)
    {
        _sentMessages = sentMessages;
    }

    public void SendMessage(string Message)
    {
        _sentMessages.Add(Message);
    }

    //rest of non-implemented methods
}

在你的单元测试中，这样做:

var sentMessages = new List<string>();
var mockedTcpClient = new TcpClientMock(sentMessages);

然后创建您要测试的任何类并对其进行操作。完成后，查看 sentMessages 是否包含您期望的消息。

---

至于接收数据，我想您需要告诉您的模拟对象引发该事件，以便您可以验证您的类在事件引发时是否按预期响应。您可以像这样向 TcpClientMock 添加一个方法:

public void SimulateDataReceived(object sender, DataReceivedEventHandlerArgs args)
{
    DataReceived(sender, args);
}

这样，当您设置了依赖于 ITCPClient 的类时，您可以在 mock 上调用 SimulateDataReceived，使其引发事件，这反过来又会让你的测试对象使用react。