Courses.Buisness.CategoryService.GetCategoryWithCategorys C# (CSharp) Method

        public CategoryViewModelForAddEditView GetCategoryWithCategorys(int? Id)
        {
            CategoryViewModelForAddEditView categoryView = new CategoryViewModelForAddEditView();
            if (Id == null)
            {
                //для возможности не выбирать категорию
                Category noCategory = new Category { CategoryId = 0, Name = "------------Отсутствует----------", Active = true, CreatedDate = DateTime.Now, UpdatedDate = DateTime.Now };
                var listCategorys = categoryRepository.Get().ToList<Category>();
                listCategorys.Add(noCategory);
                categoryView.Categorys = new SelectList(listCategorys, "CategoryId", "Name", 0);
            }
            else
            {
                var category = categoryRepository.Get(Id.Value);
                if (category != null)
                {
                    categoryView = ConvertToCategoryViewModelForAddEditView(category);
                    //для возможности не выбирать категорию
                    Category noCategory = new Category { CategoryId = 0, Name = "------------Отсутствует----------", Active = true, CreatedDate = DateTime.Now, UpdatedDate = DateTime.Now };
                    var listCategorys = categoryRepository.Get().ToList<Category>();
                    listCategorys.Add(noCategory);
                    listCategorys.Remove(category);
                    categoryView.Categorys = new SelectList(listCategorys, "CategoryId", "Name", 0);

                }
            }
            return categoryView;
        }

 public void GetCategoryWithCategorysTest()
 {
     ICategoryService _categoryService = new CategoryService(new CategoryRepository(), new CategoryFilterFactory());
     CategoryViewModelForAddEditView actual = _categoryService.GetCategoryWithCategorys(null);
     Assert.IsNotNull(actual);
 }