Some cooker tests will ALWAYS follow the same pattern:

• create a directory and put some stuff in it
• import the directory/revision with one commit pointing to that directory/...
• cook it
• check that the stuff in the exported directory is the same as the stuff in the imported directory.

We should factor that, so that we can check for all cookers that, for instance:

• using binary paths works
• all permission types work
• complex paths work

All these should be only written only once, and the processus by which it is tested is then cooker-dependant, but not test-dependant.