Easiest way of unit testing C code with Python

Question

I've got a pile of C code that I'd like to unit test using Python's unittest library (in Windows), but I'm trying to work out the best way of interfacing the C code so that Python can execute it (and get the results back). Does anybody have any experience in the easiest way to do it?

Some ideas include:

• Wrapping the code as a Python C extension using the Python API
• Wrap the C code using SWIG
• Add a DLL wrapper to the C code and load it into Python using ctypes
• Add a small XML-RPC server to the c-code and call it using xmlrpclib (yes, I know this seems a bit far-out!)

Is there a canonical way of doing this? I'm going to be doing this quite a lot, with different C modules, so I'd like to find a way which is least effort.

Answer 1

I think that the exact solution depends on your code. Not all libraries are easily suitable for wrapping as a DLL. If your is, then ctypes is certainly the easiest way - just make a DLL out of your library and then test it with ctypes. An added bonus is that you now have your library conveniently wrapped as a standalone DLL which helps to decouple your application.

Sometimes, however, a more thorough interaction will be required between your C code and the testing Python code. Then, it's probably best to hook it as an extension, for which SWIG is a pretty good tool that will automate away most things you'll find boring about the process.