White-box Testing by Combining Deduction-based Specification Extraction and Black-box Testing Bernhard Beckert and Christoph Gladisch We propose to use deductive program verification systems to generate specifications for given programs and to then use these specifications as input for black-box testing tools. In this way, (1) the black-box testing method can make use of information about the program's structure that is contained in the specification, and (2) we get a separation of concerns and a clear interface between program analysis on the one hand and test-case generation and execution on the other hand, which allows the combination of a wide range of tools. The method for specification extraction using a program verification calculus described in this paper has been successfully implemented in the KeY program verification system.