Make all EF Core model properties virtual for mocking in unit tests with Moq and xUnit?

Question

I am using the repository pattern as suggested by the documentation for unit testing in EF Core. I have reached a point in my code where I am not able to fully test a method properly as a result of doing operations on the models from EF Core and not the DB Context.

An example of what I mean is below:

Code to be tested :

    private static void AddToUserScore(Members member)
    {
        var basePoints = 2;

        if (member.HintAsked)
        {
            basePoints--;
            member.HintAsked = false;
        }

        if (member.LocationHintAsked)
        {
            basePoints--;
            member.LocationHintAsked = false;
        }

        member.UserScore += basePoints;
    }

EF Core Context Model itself:

public class Members
{
    public int MemberId { get; set; }
    public int AppId { get; set; }
    public string Username { get; set; }
    public int UserScore { get; set; }
    public string QuestionIds { get; set; }
    public int CurrentQuestionNumber { get; set; }
    public int LocationId { get; set; }
    public bool HintAsked { get; set; }
    public bool LocationHintAsked { get; set; }
}

Unit test sample:

 var fakeMemberMock = Fixture.Create<Mock<Members>>();
 fakeMemberMock.SetupSet(members => members.HintAsked = false);
 fakeMemberMock.VerifyGet(members => members.HintAsked, Times.Exactly(1));

Since none of my model's properties are virtual, this will result in an error at runtime.

I want to know if there is any reason I should not make my EF Core models all virtual for this purpose.

I am not to sure of any sideffects this may have with interaction with my database or any pros and cons of doing this. I know virtual is generally placed on navigational properties but i do not know wether doing this on normal properties is a good idea or not.

Feel free to mention another method of going about what I am attempting that would be simpler.

Thanks in advance.

Answer 1

Let me ask, isn't testing the internals of the method too granular? The alternative would be testing the method instead of the model class. The method does a unit of work which is testable.

// test case 1
var model1 = new Members();
model1.UserScore = 10;
model1.HintAsked = true;

// run the method AddToUserScore on model

// do the asserts
Assert.Equal(..., model1.UserScore);

// test case 2
var model1 = new Members();
model1.UserScore = 10;
model1.LocationHintAsked = true;