A Few Assertions on Information Hiding

data types have little impact on software error masking as far as we can determine Inheritance is not necessarily detrimental to error masking however when combined with information hiding it may become lethal Unit testing costs increase as the depth of inheritance increases This is directly related to the increase in the number of drivers and stubs As a counter argument subclasses tend to become simpler in deep complex inheritance trees and will therefore increase the ability to assess high reliability of the subclasses This presents another related problem composing reusable subclasses that are reliable Polymorphism is di cult to test i e nd test cases to exercise di er ent binding scenarios However from our previous intuition and this e ort s experimentation polymorphism when faulty will likely cause the faults to be of larger sizes suggesting decreased error masking Therefore polymorphism is not problematic for system level testing