Gatsby: Add Loki to npm test script

[stefanprobst]

Now that we are testing with Loki in CI, should we also adjust the npm jest script (or add a jest:loki script?)

[pieh]

Good question. For the most part this doesn't matter for 99% of contributors because they don't touch code related to nodes data store / sorting and filtering nodes when querying (things that are different when using loki), so maybe we could add this as connivence script (jest:loki), but don't run it when running regular jest?

[wardpeet]

how do we feel about running jest:loki in ci when gatsby-core changes?

[KyleAMathews]

We can always add more concurrency correct if builds are getting slow?

[m-allanson]

how do we feel about running jest:loki in ci when gatsby-core changes?

I like this idea 👍

[m-allanson]

Oh I misread - we already run the Loki tests in CI

[wardpeet]

@m-allanson do we? I don't think so :blush:

[pieh]

@wardpeet we do: https://github.com/gatsbyjs/gatsby/blob/master/.circleci/config.yml#L58-L59 it just wasn't worth to add another check, so it was added as step to unit tests (it adds ~30 secs to test time)