Test.cs

public abstract class Test
    {
        ...
         
        protected IFixture Fixture { get; private set; }
 
 
        [SetUp]
        public void Setup()
        {
            Fixture = new Fixture().Customize(new AutoMoqCustomization());
        }
 
        protected Mock<T> InjectMock<T>(params object[] args)
            where T : class
        {
            var mock = new Mock<T>(args);
            Fixture.Inject(mock.Object);
            return mock;
        }
    }

TestForGeneric.cs

public abstract class TestFor<TSut> : Test
        where TSut : class
    {
        private Lazy<TSut> _lazySut;
 
        /// <summary>
        /// The real object that you want to test
        /// </summary>
        protected TSut Sut => _lazySut.Value;
 
        [SetUp]
        public void SetUpTestsFor()
        {
            _lazySut = new Lazy<TSut>(CreateSut);
        }
 
        /// <summary>
        /// Create real object
        /// </summary>
        /// <returns></returns>
        protected virtual TSut CreateSut()
        {
            return Fixture.Create<TSut>();
        }
    }