Need to rewire provider-specific tests in the storage charm

[Chris Glass]

After refactoring the code in the storage charm to be a little more straightforward, the tests had to be unwired.

They need to be rewired to the top-level MAkefile "test" target somehow.

Challenges:

I think the rewiring is the easy part of the problem: the provider-specific unit tests should probably live in the storage-providers.d/ subfolder, but that isn't a python module.
- We can always hack away, but running the tests there (cd storage-providers.d/blah/ && nosetests) will break imports since the common code is not in $PYTHONPATH in that case, and making "storage-providers.d/" a python module doesn't work either (import storage-providers.d.nfs.whatever ? See the problem dot there? :) )
- Another option would be to put the provider-specific tests in the top-level directories... but in this case we can't import the things we're trying to test.

So I guess we need to tweak $PYTHONPATH in the test runner invocation to include the provider-specific folders in $PYTHONPATH, then imports should by "jumping" into storage-providers.d/, like "from nfs.hooks import blah" (skipping storage-providers.d altogether).

[Chris Glass (tribaal)]

Of course, we can always use "imp", but then we can't argue that juju is distilling best practices anymore :)

[David Britton (dpb)]

Setting to High (in expectation of Chris' branch landing)

[Cory Johns (johnsca)]

Why not have the `make test` target adjust PYTHONPATH to include the hooks directory before running the tests, and have all of the tests live in tests/unit/ or unit_tests/ off the top-level?

E.g., PYTHONPATH=hooks:$PYTHONPATH CHARM_DIR=`pwd` trial hooks

[Cory Johns (johnsca)]

Of course, that was supposed to be:

PYTHONPATH=hooks:$PYTHONPATH CHARM_DIR=`pwd` trial unit_tests