[moq] Mock object and Mock.of

 C#   Unit test   Moq

▌Introduction

---

Here are three basic ways to use Moq in unit test.

1.  Mock instance

2.  Mock.of

3.  Mock.of (Setup in lambda)

▋Related articles

1.  [moq] Mock object and Mock.of

2.  [moq] Mock delegate

3.  [moq] Mock a non-interface object

▌Environment

---

▋Visual Studio 2017 community

▋dotnet core 2.2.101

▋Moq 4.10.1

▌Implement

---

We will test the GetAge(…) function of class, BirthdayRepository. It has some dependencies inside as following,

l   IDataAccessService: responsible for fetching someone’s birthday from database

l   ILogger: Logger

▋Interfaces and Classes

▋BirthdayRespository.cs

public class BirthdayRepository : IBirthdayRepository

    {

        private IDataAccessService<Birthday> _dataAccess =null;

        private ILogger _logger = null;

        

        public BirthdayRepository(

            IDataAccessService<Birthday> dataAccess,

            ILogger logger

        )

        {

            if(dataAccess!=null) this._dataAccess = dataAccess;

            if(logger!=null) this._logger = logger;

        }

        public int GetAge(string idNumber)

        {

            Birthday birthday = this._dataAccess.Get(idNumber);

            int age = DateTime.Now.Year - birthday.Year;

            this._logger.Info($"{idNumber}'s age is {age.ToString()}");

            return age;

        }

        public void Dispose()

        {

        }

    }

▋IBirthdayRespository.cs

public interface IBirthdayRepository : IDisposable

{

        int GetAge(string idNumber);

}

▋IDataAccessService

public interface IDataAccessService<T>

    {

        string ConnectionStr { get; set; }

        T Get(string id);

    }

▋ILogger

public interface ILogger

    {

        void Info(string msg);

    }

▋Unit test by Mock instance

const int targetYear = 2001;

var birthday = new Birthday() {

       Year = targetYear,

       Month = 10,

       Day = 18

};

 int expected = DateTime.Now.Year - targetYear;

 int actual = 0;

 #region Mock instance

 var mockLogger = new Mock<ILogger>();

var mockDataAccess = new Mock<IDataAccessService<Birthday>>();

mockDataAccess.SetupProperty(s => s.ConnectionStr);

mockDataAccess.Object.ConnectionStr = string.Empty;

mockDataAccess.Setup(x => x.Get(It.IsAny<string>())).Returns(birthday);

IBirthdayRepository birthdayRepository = new BirthdayRepository(mockDataAccess.Object, mockLogger.Object);

actual = birthdayRepository.GetAge("YYYYYY");

mockDataAccess.Verify(x => x.Get(It.IsAny<string>()), Times.Once);

#endregion

Assert.AreEqual(expected, actual);

▋Unit test by Mock.of

We can replace the codes in region with Mock.of

#region Mock.of

var mockLogger = Mock.Of<ILogger>();

var mockDataAccess = Mock.Of<IDataAccessService<Birthday>>();

mockDataAccess.ConnectionStr = string.Empty;

Mock.Get(mockDataAccess).Setup(x => x.Get(It.IsAny<string>())).Returns(birthday);

IBirthdayRepository birthdayRepository = new BirthdayRepository(mockDataAccess, mockLogger);

 actual = birthdayRepository.GetAge("YYYYYY");

 #endregion

▋Unit test by Mock.of (Setup in lambda)

Or even graceful,

#region Mock.of (Setup in lambda)

var mockLogger = Mock.Of<ILogger>();

var mockDataAccess = Mock.Of<IDataAccessService<Birthday>>(x => x.ConnectionStr == string.Empty && x.Get(It.IsAny<string>()) == birthday);

IBirthdayRepository birthdayRepository = new BirthdayRepository(mockDataAccess, mockLogger);

actual = birthdayRepository.GetAge("YYYYYY");

#endregion

▌Reference

---

▋Improve your unit tests with Moq and Mock.Of<>()

▋Unable to Mock HttpClient PostAsync() in unit tests