public void GetAllTest()
        {
            //Arrange
            var producers = new List <Producer>
            {
                new Producer {
                    Id = 1,
                },
                new Producer {
                    Id = 2
                },
                new Producer {
                    Id = 3
                },
            };

            using (var context = new AppDbContext(options))
            {
                var repo = new ProducerRepository(context);

                //Act
                foreach (var producer in producers)
                {
                    context.Producers.Add(producer);
                }
                var result = repo.GetAll();

                //Assert
                Assert.AreEqual(context.Orders, result);
            }
        }