Add pygments for tests session

[cjolowicz]

pytest provides useful colored backtraces when pygments can be imported.

Need to decide if this should be in the template, or if it's better aligned with the project goal of simplicity and minimalism to omit this dependency, and leave it to the user.

[staticdev]

I found that useful specially locally. I think the dev-dependencies complexity is increased but the developer life is also simplified when there is an error on their unit tests =p

There is also a marginal increase in CI test session (but pygments don't have other dependecies). Do you think it is possible to cache installed dependencies on Github Actions to reduce test time? My macos test sessions are always the last one to finish (from all sessions).

[cjolowicz]

I found that useful specially locally. I think the dev-dependencies complexity is increased but the developer life is also simplified when there is an error on their unit tests =p

No question about it being useful. I'm still not sure about including it in the template, though. It's not an essential feature, and simple for users to add in their own projects. How much bells and whistles do we want in the template?

There is also a marginal increase in CI test session (but pygments don't have other dependecies). Do you think it is possible to cache installed dependencies on Github Actions to reduce test time? My macos test sessions are always the last one to finish (from all sessions).

Yes. Last I looked it didn't make a lot of difference to us. But it seems a good idea anyway to promote caching pip dependencies, as it takes load off PyPI, and it may make a difference to some projects. This used to be very verbose, but recently pip has gained pip cache dir. I think I also heard about a GH action for this (not sure). So feel free to open a separate issue and/or a pull request.

See https://github.com/actions/cache/blob/master/examples.md#using-pip-to-get-cache-location

[staticdev]

I think a way of helping you decide is shifting a bit the discussion from minimalism x adding bells and whistles.

Usually, when I create templates for my team, the question I ask myself is: do I always want this feature in my projects? Or there is simpler projects that I wouldn't want that? If the answer to the first question is yes (and second is no), I would absolutely add this to the project, since it saves people time from adding it by hand.

About pip cache, issue created #406