Code review comment for lp:~viswesn/juju-ci-tools/ensure_provider_cleanup

You haven't answered the questions or given reason for the changes that differ to the requests from the previous review (namely repr vs str and the ability to store better details on why the delete failed). Please respond.

Also you seemed to have ignored the comments surrounding contains_only_known_instances (using issubset and removing the method). Please respond.

I've identified concerns with the testing below, namely patching the wrong then and incorrect asserts.