LGTM alerts: Python test suite alerts

[ronaldtse]

Description

32 alerts in total. Too long to paste... See for yourself...

https://lgtm.com/projects/g/rnpgp/rnp/alerts/?mode=list&lang=python

[ni4]

@ronaldtse I'll handle this. While it's only tests, still should have good coding style )

[ronaldtse]

Thanks @ni4!