Expose pytest integration as a plugin

[vodik]

So, was going to put this off until I got some of my other ideas completed, but someone just opened an issue on an old project I started the last time I was playing with Hy: vodik/hytest#1

That project was me fiddling with writing a pytest plugin that integrated Hy into pytest.

But we already do this. So, my proposal is to do the following:

• Move the Hy specific logic out of conftest.py and move it somewhere inside the hy package (say hy.contrib.pytest_plugin)
• Update conftest.py to use pytest_plugins = ['hy.contrib.pytest_plugin']

Now we have two options for exposing this to the general pytest community:

1. Hy itself could register a pytest plugin directly as an entry_point.
2. Publish another package under hylang organization called something like pytest-hy that registers a pytest plugin which contains a single line along the lines of:

from hy.contrib.pytest_plugin import *

I'm more in favour of the later, as its more explicit. It is also how I've seen other libraries do it, for example pytest-aiohttp

We could also promote a few useful functions like can_compile, can_eval, etc as pytest fixtures for other projects to reuse.

[Kodiologist]

Sounds cool. I'd lean toward option 1 because otherwise we'd create a lot of organization and boilerplate (a GitHub repo, a PyPI package, etc.) for a one-liner. Users will already have to add "hy.contrib.pytest_plugin" to their pytest_plugins, which seems explicit to me.

I would name it hy.extra.pytest_plugin or just hy.pytest_plugin rather than hy.contrib.pytest_plugin.

[vodik]

We can start with option 1 and move to option 2 if it ever becomes a problem with it being a default.

[arjaz]

Hi!
I created a plugin for pytest for my needs which is based on the hy's conftest.py!
I'll be glad to see it integrated.

[Kodiologist]

Cool, thanks. Perhaps we'll do that.

[Kodiologist]

At this point, you can get pytest working with Hy with about 5 lines of configuration, so I've documented them on the wiki, and a plugin seems like overkill.