public void BasicTaxType_With_Negative_TaxRate_Is_Invalid()
 {
     var type = new BasicDutyType("Book") {TaxRate = -0.1};
     Assert.IsFalse(type.IsValid);
 }
 public void BasicTaxTypes_Should_Be_Equal_With_The_Same_Name()
 {
     var type1 = new BasicDutyType("Book");
     var type2 = new BasicDutyType("Book");
     Assert.AreEqual(type1, type2);
 }