Test Cleanup
- Traced the codes again to find the reason of failure.
Well, there are some items which have an acl of their own, i.e. backend._get_acl(test_item.name) = True. Now this acl is checked before the default one and AccessDeniedError is returned as it should
- For the items having an acl of their own i.e. with backend._get_acl(test_item.name) = True, backend.before.acl can be altered to serve the purpose.
- Removed app initialization from tests in storage, datastruct and apps as they are not required anymore after the clean up, thus making the tests faster.