public void CannotHaveValueObjectWithDomainSignatureProperties() {
            ValueObjectWithDomainSignature invalidValueObject =
                new ValueObjectWithDomainSignature();

            Assert.Throws<PreconditionException>(
                () => invalidValueObject.GetSignatureProperties()
            );
        }
        public void CannotHaveValueObjectWithDomainSignatureProperties()
        {
            ValueObjectWithDomainSignature invalidValueObject =
                new ValueObjectWithDomainSignature();

            Assert.Throws <PreconditionException>(
                () => invalidValueObject.GetSignatureProperties()
                );
        }