public void TestThatLongNameThrowsOnEmptyString()
        {
            var attrib = new ArgumentValueAttribute();

            attrib.Invoking(a => a.LongName = string.Empty)
            .Should().Throw <InvalidArgumentSetException>();
        }
        public void TestThatLongNameAcceptsNull()
        {
            var attrib = new ArgumentValueAttribute();

            attrib.Invoking(a => a.LongName = null)
            .Should().NotThrow <InvalidArgumentSetException>();
        }