Most of the application testing focuses on the inter- face between the user and the application. However, soft- ware applications do not only interact with their users but also with resources and remote entities. Some recent ap- proaches focus on testing the interface between the appli- cation code and the underlying software components like shared libraries. For example, one interesting approach is error injection [1, 3] where possible error return values of library functions are injected at the interface between the application code and the shared libraries.