public void AndSpecification_IsValid_1of2SpecsIsTrue_thrValidationException() { ISpecification <string> isNotEmptySpec = new IsNotEmptySpecification(); ISpecification <string> isNullSpec = new IsNullSpecification <string>(); AndSpecification <string> andSpec = new AndSpecification <string>(isNotEmptySpec, isNullSpec); Assert.Throws <ValidationException>(() => { andSpec.IsValid(""); }); }