testtools was recently bumped to a version that is typed, which means we now see type hints for that library. As a result, we now see issues with variables defined in tests via setUpClass. Note that the issue lies with mypy and not testtools, however: mypy doesn't adding class variables via assignment [1]. [1] https://github.com/python/mypy/issues/8723 Change-Id: I8b09846ff8fc6ee51ba03531f5b41039282ee1c0 Signed-off-by: Stephen Finucane <stephenfin@redhat.com>