Code review comment for ~stanley31/plainbox-provider-checkbox:wwan_fixed

A few requests to make this easier to process:

- the "task_type" mechanism seems a bit strange - it looks to me like you could just `raise SystemExit("<Fail info..>")` at the point the test fails and not do all this handling later on
- addition of logging could be considered an improvement, but not necessary to fix the bug and distracts from understanding the change, i would remove it for now
- please follow the contribution guide and make sure the commit message is the format requested