public void CheckEmployerExistAfterDelete()
        {
            //Arrange
            Employer employer1 = new Employer()
            {
                Id   = 66,
                Name = "test",
                NIP  = "unit"
            };
            Employer employer2 = new Employer()
            {
                Id   = 77,
                Name = "test",
                NIP  = "unit"
            };

            var options = new DbContextOptionsBuilder <Context>()
                          .UseInMemoryDatabase(databaseName: "UsersDirectoryMVC")
                          .Options;

            using (var context = new Context(options))
            {
                //Act
                var employerRepository = new EmployerRepository(context);
                employerRepository.AddEmployer(employer1);
                employerRepository.AddEmployer(employer2);
                employerRepository.DeleteEmployer(66);
                var gerEmployer1 = employerRepository.GetEmployer(66);
                var gerEmployer2 = employerRepository.GetEmployer(77);
                //Assert
                gerEmployer1.Should().BeNull();
                gerEmployer2.Should().Equals(employer2);
            }
        }