public void IsSatisfiedBy_WithFilledString_ReturnsTrue()
        {
            var specification = new StringNotNullOrWhiteSpace();
            var result        = specification.IsSatisfiedBy("hello world");

            result.ShouldBeTrue();
        }
        public void IsSatisfiedBy_ReturnsFalse(string subject)
        {
            var specification = new StringNotNullOrWhiteSpace();
            var result        = specification.IsSatisfiedBy(subject);

            result.ShouldBeFalse();
        }