Three Patterns in Java Unit Testing.

This paper discusses three unit-testing techniques. These are test probe, ipecac, and test hierarchies. Each of these patterns [1] explores a different area of the interaction of white- and black-box testing. The first two techniques, test probe and ipecac, allow internal implementations to be conveniently exposed to test code without compromising production code integrity. The latter provides a pattern for testing class hierarchies in production code, and a way to move from white-box to black-box testing while refactoring.