title: trickle down unit tests
body: <p>If I'm writing a library in C that includes a Python interface, is it OK to just write unit tests for the functions, etc in the Python interface? Assuming the Python interface is complete, it should imply the C code works.</p>
  
  <p>Mostly I'm being lazy in that the Python unit test thing takes almost zero effort to use.</p>
  
  <p>thanks,
  -nick</p>