public void EqualityIsDeterminedByContent()
        {
            sut = PostOfficeBoxPostalCode.Create(ValidPostalCode);
            PostOfficeBoxPostalCode other = PostOfficeBoxPostalCode.Create(ValidPostalCode);

            Assert.AreEqual(other, sut);
        }
        public void DoesNotEqualToDifferentTypeObject()
        {
            sut = PostOfficeBoxPostalCode.Create(ValidPostalCode);

            Assert.AreNotEqual(ValidPostalCode, sut);
        }
        public void FiveDigitPostalCodeThatDoesntEndWithZero()
        {
            sut = PostOfficeBoxPostalCode.Create(ValidPostalCode);

            Assert.AreEqual(ValidPostalCode, sut.ToString());
        }