brucker.ea:interactive:2005 BookSection Heidelberg Springer-Verlag 2005 Formal Approaches to Testing of Software 3997 BruckerAchimD WolffBurkhart GrieskampWolfgang WeiseCarsten Interactive Testing using HOL-TestGen HOL-TestGen is a test environment for specification-based unit testing build upon the proof assistant Isabelle/HOL\@. While there is considerable skepticism with regard to interactive theorem provers in testing communities, we argue that they are a natural choice for (automated) symbolic computations underlying systematic tests. This holds in particular for the development on non-trivial formal test plans of complex software, where some parts of the overall activity require inherently guidance by a test engineer. In this paper, we present the underlying methods for both black box and white box testing in interactive unit test scenarios. HOL-TestGen can also be understood as a unifying technical and conceptual framework for presenting and investigating the variety of unit test techniques in a logically consistent way.