Puppeteer/Lighthouse

[bryophyta]

We have some gaps in our Lighthouse coverage around e.g. content that's only loaded on the client-side on scroll or interaction. We can integrate with Puppeteer to run Lighthouse in a more 'integration test' style.

• Implement this for Accessibility tests.
• Investigate whether/how it could be useful for the other performance measures.

[VDuczekW]

there need to be a wider discussion on accessibility - rather than tackle singular @jamesgorrie @bryophyta

[bryophyta]

@bryophyta to see if there's a quick fix to improve coverage; if it's a bigger piece of work then it should be planned separately

[bryophyta]

Update: You can provide a custom puppeteer script to Lighthouse CI, but it seems like this script is only run once, before the actual Lighthouse script is, so any hydration from the script is lost by the time Lighthouse actually runs.

I've written a node script that will collect the accessibility scores with a custom puppeteer script that scrolls down to the onwards container and waits for it to hydrate. I've verified that this catches issues that aren't caught by the regular Lighthouse CI action. However, because it's separate from Lighthouse CI the results won't be surfaced automatically by our current action. So we need to work out whether/how to surface the results. I've started drafting a modification of lighthouse.yml GHA workflow but it would be good to check what we want to do with the results before spending too much time on this surfacing task.