Thanks Rémy, 

About testing, I would go for modules with errors in it and check that when imported trough this function it does what it is supposed to do.

IOW:

1. Create a test python module with errors in their definition (Throw an exception would do the trick)
2a. Try to load this python module, check that the exception is the one thrown in the module
2.b Check that loading a non existing modules still tell us that the module doesn't exist
2.c Check that importing something existing works, trough this function. 

Hope I'm clear enough, thanks again,
Alexis