using System;

using Xunit;

using Moq;

​

public class LoginModel

{

    public string Name {get; set;}

    public string Password {get; set;}

    public DateTime LastLogin {get;set;}

}

​

public interface IDbStorage 

{

    void Save<T>(T entity);

}

​

public class LoginManager

{

    private readonly IDbStorage _storage;

    public LoginManager(IDbStorage storage)

    {

        _storage = storage;

    }

    public void LogIn(LoginModel model) 

    {

        model.LastLogin = DateTime.UtcNow;

        _storage.Save(model);

    }

}

​

​

public class LoginManagerTests

{

    [Fact]

    public void LogIn_should_update_lastlogin_field()

    {

        //arrange

        var storageMoq = new Mock<IDbStorage>();

        var manager = new LoginManager(storageMoq.Object);

        var model = new LoginModel

        {

            LastLogin = DateTime.MinValue

        };

        //act

        manager.LogIn(model);

        //asset 

        Assert.True((model.LastLogin - DateTime.UtcNow).Seconds <= 1);

    }

​

    [Fact]

    public void LogIn_should_save_model_in_db()

    {

        //arrange

        var storageMoq = new Mock<IDbStorage>();

        var manager = new LoginManager(storageMoq.Object);

        var model = new LoginModel

        {

            LastLogin = DateTime.MinValue

        };

        //act

        manager.LogIn(model);

        //asset 

        storageMoq.Verify(c => c.Save(model), Times.Once());

    }

}

​

​