public void Should_be_able_to_get_controll_number()
        {
            PersonalNumber personalNumber = new PersonalNumber("800531-8996");

            int checkNumber = personalNumber.GetControllNumber();

            checkNumber.Should().Be(6);
        }
 public void A_correct_number_should_be_valid()
 {
     PersonalNumber personalNumber = new PersonalNumber("800531-8996");
     Assert.That(personalNumber.IsValid);
 }