Integrate AutoMapper in my Unit Test doesn't work

Question

My problem is that I am trying to add AutoMapper in my unit test, but I have one method that doesn't pass. I've tried to add to configure AutoMapper in the constructor, but it's still not working. I am not a pro in unit test, so can someone help me with this please.

public AssetControllerTest() 
{
    _loggerMock = new Mock<ILogger<AssetController>>();
    _sqlService = new Mock<ISqlService>();

    //_mapper = new Mock<IMapper>();

    if (_mapper == null)
    {
        var mappingConfig = new MapperConfiguration(mc =>
            {
                mc.AddProfile(new AssetProfile());
            });
        IMapper mapper = mappingConfig.CreateMapper();
        _mapper = new Mock<IMapper>();
    }
}

This the test method

This one is the controller