Command line arguments don't work for pytester plugin

[ionelmc]

Because it's not active by default arguments like --runpytest=subprocess are not recognized:

usage: py.test [options] [file_or_dir] [file_or_dir] [...]
py.test: error: unrecognized arguments: --runpytest=subprocess
  inifile: /home/ionel/osp/pytest-cov/setup.cfg
  rootdir: /home/ionel/osp/pytest-cov

Maybe the argument parsing for pytester should be moved in core?

[nicoddemus]

_pytester is not loaded by default because it is only useful for plugin authors. Besides the little import time cost, it would also appear in the list of plugins, so this might seem strange for the regular user. To workaround that you have to pass -p pytester in the command line (or in your pytest.ini).

(Based on your recent commits into pytest-cov I'm sure you are aware of that, but I'm writing this anyway for the benefit of those who don't have this background 😄 )

Just moving the options to the core wouldn't be enough, as something (still in core) would have to see that pytester-related options are set, and then load pytester... I'm not sure it is worth the hassle, specially because pytester is meant for plugin authors only. What do you think?

[ionelmc]

I don't want it that bad, using '-p' seems reasonable.

Though there's one additional problem, on 2.7 there's no --runpytest argument. I have to create this workaround in a conftest.py to make the tests run on 2.7:

def pytest_configure(config):
    config.option.runpytest = 'subprocess'

Would be worth to at least document this.

[nicoddemus]

I think pytester itself deserves some documentation, including examples on how to write tests for plugins you write yourself.

We should open a new issue for it, and then of course --runpytest could be documented properly. What do you think?

[ionelmc]

I agree but I don't wanna do it, just slowly learning what in that plugin 😁

[nicoddemus]

OK, created #971 😄