public async Task CheckGettingAllAsSelectListItemAsync()
        {
            ApplicationDbContext db = GetDb();

            var repository = new EfDeletableEntityRepository <Brand>(db);
            var service    = new BrandsService(repository);

            var firstBrand = new Brand()
            {
                Id = Guid.NewGuid().ToString()
            };
            var secondBrand = new Brand()
            {
                Id = Guid.NewGuid().ToString()
            };
            var thirdBrand = new Brand()
            {
                Id = Guid.NewGuid().ToString()
            };

            await db.Brands.AddAsync(firstBrand);

            await db.Brands.AddAsync(secondBrand);

            await db.Brands.AddAsync(thirdBrand);

            await db.SaveChangesAsync();

            var brands = await service.GetAllAsSelectListItemAsync();

            Assert.Equal(3, brands.Count());
        }