Support Pytest 4

[duritong]

Fedora migrated for Rawhide to Pytest 4: https://lists.fedoraproject.org/archives/list/devel-announce@lists.fedoraproject.org/thread/XD4FRORMUMQBLXJSHUHP6B6AAFZBKSL4/

This breaks the test and thus the builds: https://apps.fedoraproject.org/koschei/package/python-onionbalance?collection=f31

[687766616e]

Is it no longer updated?

[duritong]

It fails to build from source, as part of the build process runs the tests. If the package can't be built, it will eventually get removed from Fedora.

[duritong]

https://bugzilla.redhat.com/show_bug.cgi?id=1736518