ksensor tests are a bit environment dependent
There are two issues with the ksensor tests currently:
1. There is a missing package dependency between the os-tests and the ksensor package. Without this the tests themselves will not work. However, it's easy to miss this if you're doing development on this because you'll always have it installed.
2. The test runner, somewhat surprisingly has separate users that you need to indicate for the pre/post scripts and does not fallback on user. This meant that the calls to add_drv/rem_drv were failing because they were being run as an unprivileged user or were dependent on how they were invoked.
Both of these fixes are simple and should make this part of the test suite more reliable.