`argparse.HelpFormatter` looks at `$COLUMNS` only, falling back to a
default of 80.
`py.io.get_terminal_width()` is smarter there, and could even work
better with https://github.com/pytest-dev/py/pull/219.
This ensures to use a consistent value for formatting the ini values etc.
It seems pytest's very comprehensive CI sniffed out a few other places with similar bugs. Ideally we should find all the places where args are not stringy and solve it at the source, but who knows how many people are relying on the implicit string conversion. See [here](https://github.com/pytest-dev/pytest/blob/master/src/_pytest/config/__init__.py#L160-L166) for one such problem area (args with a single py.path.local instance is converted here, but a list or tuple containing some are not).
Daniel Hahler
Semen Zhydenko
Bruno Oliveira
Zac Hatfield-Dodds
Anthony Sottile
Ville Skyttä
CrazyMerlyn
wim glenn
Bruno Oliveira
Ronny Pfannschmidt