Run coverage at the end of jest and configure thresholds

[oorestisime]

So i enabled (again it seems) the coverage tests and added a threshold using jest-coverage-ratchet

Questions for improvement

1. should i add thresholds for each package not just a global feel?
2. there is a prepush hook to configure with jest-coverage-ratchet to automatically adjust the thresholds. i could look how to add that
3. if the answer for 2 is no then i am not sure i should add jest-coverage-ratchet in dependencies

[oorestisime]

I was trying to look at which packages lack in tests and i realized that the current configuration was lacking since it wasn't getting the coverage from all available sources hence i modified it.

In addition i ve remove ratchet since i dont feel like it is really useful in the end.

[m-allanson]

Thanks @oorestisime, this looks great 👍

I've switched this over to default to coverage off, with a new npm command to run tests with coverage. I think that gives us a good chance to experiment with running this in CI, and using different threshold levels, along with maybe adding jest-coverage-ratchet back in?

Regarding threshold levels - maybe the next step could be to pick out some core packages and group them together with one threshold setting. Then use a separate threshold for everything else.

A list of 'core' packages might be something like:

• babel-plugin-remove-graphql-queries
• gatsby
• gatsby-image
• gatsby-link
• gatsby-plugin-page-creator
• gatsby-plugin-sharp

[oorestisime]

Yes definitely! I can play again with threshold levels later today and get back here!

[m-allanson]

Merging, thank you!