python setup.py test returns non-zero exit code on first invokation

``` sh
usage: setup.py [options] [file_or_dir] [file_or_dir] [...]

setup.py: error: unrecognized arguments: --cov --cov-report term tests

The command "python setup.py test" exited with 2.

Done. Your build exited with 1.
```

If the maintainer(s) are still active on this project, I'll submit a PR
