public void Successor_ValidInput_ReturnsCorrectPostalCode(string postalCode, string postalCodeSuccessor) { var code = new LUPostalCode(postalCode); var codeSuccessor = new LUPostalCode(postalCodeSuccessor); Assert.AreEqual(codeSuccessor, code.Successor); Assert.AreEqual(codeSuccessor.ToString(), code.Successor.ToString()); Assert.AreEqual(codeSuccessor.ToHumanReadableString(), code.Successor.ToHumanReadableString()); }