first local test run requires `npm run build`

[zeke]

A fresh clone of this repo requires npm run build to be run before all the tests will pass. This is an easy thing to forget because you only have to run it once and then npm test continues to work without a fresh build.

One way we can work around this is by adding a pretest script to package.json with a value of npm run build. That way the build will always run first when anyone runs npm test.

That would solve the immediate problem for first-time contributors, but it would also incur a performance penalty every time you run the tests locally, as the build currently takes ~4 seconds to run on my superfast computer. Maybe 4s doesn't matter much in the grand scheme of things... but it would be nice to not incur that cost.

🤔 What are some ways we can solve this?

cc @github/docs-engineering @jeffmcaffer

[github-actions]

This issue is stale because it has been open 60 days with no activity.

[JamesMGreene]

For the short term, we've also clarified this in the contributing/development documentation: 054f9ab