At the validation or system level, the details of class
connections disappear. Like conventional validation, the validation of OO software focuses on user-visible actions
and user-recognizable output from the system. To assist in
the derivation of validation tests, the tester should draw upon
the use-cases that are part of the analysis model. The use-
case provides a scenario that has a high likelihood of
uncovered errors in user interaction requirements.
Conventional black box testing methods can be used to drive
validations tests. In addition, test cases may be derived from
the object-behavior model and from event flow diagram
created as part of object oriented analysis (OOA).