public async Task ManufacturerRepositoryMethodAllTest()
        {
            var options = new DbContextOptionsBuilder <ManufacturerDbContext>()
                          .UseInMemoryDatabase(databaseName: "ManufacturerApp").Options;

            // Add() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                var repository   = new ManufacturerRepository(context);
                var manufacturer = new Manufacturer()
                {
                    Name = "SAMSUNG", ManufacturerCode = "SM", Comment = "삼성"
                };
                await repository.AddManufacturerAsync(manufacturer); // 입력 메서드 테스트

                await context.SaveChangesAsync();
            }
            using (var context = new ManufacturerDbContext(options))
            {
                Assert.AreEqual(1, await context.Manufacturers.CountAsync());
                var manufacturer = await context.Manufacturers.Where(m => m.Id == 1).SingleOrDefaultAsync();

                Assert.AreEqual("SM", manufacturer.ManufacturerCode);
            }

            // GetAll() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                await(new ManufacturerRepository(context)).AddManufacturerAsync(
                    new Manufacturer()
                {
                    Name = "LG", ManufacturerCode = "LG", Comment = "LG"
                });
                await context.SaveChangesAsync();
            }
            using (var context = new ManufacturerDbContext(options))
            {
                var repository    = new ManufacturerRepository(context);
                var manufacturers = await repository.GetManufacturersAsync();

                Assert.AreEqual(2, manufacturers.Count());
            }

            // GetByIdAsync() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                await(new ManufacturerRepository(context)).AddManufacturerAsync(
                    new Manufacturer()
                {
                    Name = "SK", ManufacturerCode = "SK", Comment = "SK"
                });
                await context.SaveChangesAsync();
            }
            using (var context = new ManufacturerDbContext(options))
            {
                var repository = new ManufacturerRepository(context);
                var sk         = await repository.GetManufacturerAsync(3);

                Assert.AreEqual("SK", sk.Comment);
            }

            // EditAsync() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                await(new ManufacturerRepository(context)).AddManufacturerAsync(
                    new Manufacturer()
                {
                    Name = "MS", ManufacturerCode = "MS", Comment = "MS"
                });
                await context.SaveChangesAsync();
            }
            using (var context = new ManufacturerDbContext(options))
            {
                var repository = new ManufacturerRepository(context);
                var microsoft  = await repository.GetManufacturerAsync(4);

                microsoft.Name = "마이크로소프트";
                await repository.EditManufacturerAsync(microsoft);

                await context.SaveChangesAsync();

                var microsoftNew = await repository.GetManufacturerAsync(4);

                Assert.AreEqual("마이크로소프트", microsoftNew.Name);
            }

            // DeleteAsync() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                // Empty
            }
            using (var context = new ManufacturerDbContext(options))
            {
                var repository = new ManufacturerRepository(context);
                await repository.DeleteManufacturerAsync(1);

                await repository.DeleteManufacturerAsync(2);

                await repository.DeleteManufacturerAsync(3);

                Assert.AreEqual(1, await context.Manufacturers.CountAsync());
            }

            // GetAllByPageAsync() Method Test
            using (var context = new ManufacturerDbContext(options))
            {
                // Empty
            }
            using (var context = new ManufacturerDbContext(options))
            {
                int pageIndex = 0;
                int pageSize  = 2;

                var repository    = new ManufacturerRepository(context);
                var manufacturers = await repository.GetAllByPageAsync(pageIndex, pageSize);

                Assert.AreEqual(1, manufacturers.TotalRecords);
                Assert.AreEqual(1, manufacturers.Records.ToList().Count());
            }
        }