openfecli tests require nagl

[mikemhenry]

Running the CLI tests without NAGL in your env results in a handful of tests failing: The NAGL toolkit is not available, you may be using an older version of the OpenFF toolkit - you need v0.14.4 or above We should setup our tests to skip these tests if NAGL isn't installed.

[IAlibay]

I'm not too keen on a torch dependency, but how do we feel about just making Nagl-base a build requirement?

[mikemhenry]

if nagl-base is enough for the tests to pass, then I don't think it is a bad idea, my fix for this was to just make the tests only run if nagl is in the env, not add nagl as a runtime dep for openfe

[IAlibay]

Yeah I think we only need Nagl-base. @jthorton might know better here.

[mikemhenry]

Even base pulls in pytorch https://github.com/conda-forge/openff-nagl-feedstock/blob/main/recipe/meta.yaml#L37

[IAlibay]

:/ I don't know then.

The view from "up top" is that NAGL is going to become a common place tool in our pipelines, iirc the next OpenFF release is going to be parameterised using NAGL. That being said, I don't have (or want to have) any strong takes at what this means at the package level. If dependency size is a big deal, we should report it upstream, it's a legit concern openfe partners have raised.

[mikemhenry]

Well for now we can just skip running the tests in the openfecli like we do in openfe if the package doesn't exist, I would like to create gufe-base and openfe-base packages that don't have things like charge backends and md engines anyway

[jthorton]

Ah yes we should have added the skip if not installed in the first place while NAGL is still considered optional. I could also mock the charge generation if we don't want most tests to use nagl this was just to keep the CI quick but mocking would work here as well!

[mikemhenry]

I think we are okay, since if a user installs nagl then the tests will run, and we have nagl installed on our CI env.

We might want to update the install instructions to say "also install whatever charge backend you are going to use before you run the tests so that it gets tested"