Database scope for many to many ASP.NET

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ASP.NET

MVC

entity-framework

I have problem with many-to-many relationship. ive implemented GenericRepository and UnitOfWork pattern.

i have 2 entities, Test and Question

the problem is that when i call these 2 entities from database and want to link them in link table ef is duplicating then in their respective tables. I believe this could be solved with using(var context = new MyDbContext()) statement and linking them inside that using statement but unfortunately UnitOfWork dont allow that, so ive tried using (var scope = new TransactionScope()) with no luck.

for example: i have 5 questions in database and 3 answers for each question and after user is done with test i figure out user score and insert new test row with some data. link table is here to show what questions did user had for that test. when i save test entity every single question and answer is duplicated to database.

public int SaveTestResult(TestEntity testEntity)
    {
        using (var scope = new TransactionScope() )
        {

            testEntity.Questions = testEntity.Questions.OrderBy(q => q.Id).ToList();
            var idlist = testEntity.Questions.Select(x => x.Id).ToList(); // get ids from list of questions from testentity

            //note:i believe this line is causing that behaviour 
            var questionss = _unitOfWork.QuestionRepository.GetMany(q => idlist.Contains(q.Id)).OrderBy(q => q.Id).ToList();//get questions from ids and sort them by id  
            var questions = AutoMapper.Mapper.Map<List<Question>, List<QuestionEntity>>(questionss); //map from Question from db to QuestionEntity
            testEntity.Questions = testEntity.Questions.OrderBy(q => q.Id).ToList();//sort testEtities questions id to match questions above
            var number= 0;
            for (int i = 0; i < testEntity.Questions.Count; i++)
            {
                for (int j = 0; j < testEntity.Questions[i].Answers.Count; j++)
                {
                    if ((testEntity.Questions[i].Answers[j].IsTrueUserChoice == questions[i].Answers[j].IsTrue) && (questions[i].Answers[j].IsTrue == true))
                        number++;
                }
            }

            testEntity.TestScore = number;
            testEntity.Questions = questions;//ading questions from db so model validation would pass. quesiton from testEntiy are not valid, some properties are missing
            var testDb = new Test();
            testDb.TestTime = (testDb.TestDateEnd - testEntity.TestDateStart).Value;
            testDb.TestDateStart = testEntity.TestDateStart.Value;
            testDb.TestScore = testEntity.TestScore;
            testDb.UserId = testEntity.UserId;
            testDb.Questions = AutoMapper.Mapper.Map<List<QuestionEntity>, List<Question>>(testEntity.Questions);
            _unitOfWork.TestRepository.Insert(testDb);
            _unitOfWork.Save();
            scope.Complete();
            return number;
        }
    }

note: dont get caught up in logic ive implemented :) focus on problem thanks

What I have tried:

every solution on stackoverflow