Hello, It is common practice to export only selected entities from a Haskell module and refrain from exporting other entities so that they are only available for internal use. There are many reasons for wanting to do this, such as reducing the number of importable entities, avoiding the exposure of internal details that may therefore more easily be changed, and to enable certain optimizations (http://haskell.org/haskellwiki/Performance/Modules). However, for one particular use, namely automated testing, it often seems useful, even necessary, to allow even entities considered internal to be exported: If internal entities cannot be imported by the testing code, they can only be tested indirectly, via the exported entities, and that may turn out to be troublesome. A possibility would be to include the testing code in the module itself, but that seems clumsy and wasteful. For possible guidance, I have looked at http://darcs.haskell.org/packages/filepath and System/FilePath/Internal.hs contains

-- Note: leave this section to enable some of the tests to work #ifdef TESTING -- * Drive methods splitDrive, joinDrive, takeDrive, replaceDrive, hasDrive, dropDrive, isDrive, #endif

precisely to allow automated testing. And that, of course, solves the problem. But I am wondering whether other solutions to this problem could be found, perhaps even solutions that stay within the limits of the Haskell language itself? If anybody know of alternative solutions, I would very much like to hear about them. Thanks and best regards Thorkil