SQA Engineer Question:

In the object-oriented view of testing, tests are isolated at a smaller scope, yet can have high complexity due to the interfaces with other objects. The object-oriented view of testing must be able to deal with classes, methods, and attributes and to validate those at a high level of coverage.

In Shel Siegel's book, "Object-Oriented Software Testing," he describes the Hierarchical approach to O-O testing.