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c#unit-testinginheritancesftpwrapper

SftpClient Unit test derived class and mock base class C#

I have a wrapper around Renci.SshNet.Sftp.SftpClient. I want to unit test this wrapper.

my wrapper

public class MySftpClient: SftpClient, IMySftpClient
{
    public MySftpClient(string host, int port, string username, string password) : base(new PasswordConnectionInfo(host, port, username, password)) { }

    public new void Connect()
    {
        base.Connect();
    }
}

unit test

[TestMethod]
public void Connect_Successful_Valid()
{
    var mySftpClient = new MySftpClient("localhost", 22, "root", "password");

    mySftpClient.Connect();
    // This errors because it actually tries to connect to a server using the above mock connection data
    // I cannot assert method Connect() was called once.
}

  1. Can I mock the base class method? Or should I make an interface around the SftpClient and inject it into the constructor of MySftpClient, prefering composition over inheritance?

  2. Should I use .Net DI Injection for SftpClient? services.AddScoped<ISftpClient, SftpClient>();

possible solution

public class MySftpClient: IMySftpClient
{
    private ISftpClient sftpClient;

    public MySftpClient(
        ISftpClient sftpClient,
        string host,
        int port,
        string username,
        string password
    ) { // Instantiate PasswordConnectionInfo... }

    public void Connect()
    {
        sftpClient.Connect();
    }
}
Solution

  • The best solution at the moment is to exclude our own SftpClient wrapper from unit test coverage.
    https://github.com/sshnet/SSH.NET/issues/890#issuecomment-957179713

    A pull request was merged with an interface having Connect() method. But currently it is not merged into master.
    https://github.com/sshnet/SSH.NET/pull/975

    SftpClientWrapper