At the beginning of the project, Jest (our testing framework) was only freshly added to Core. Since then, we've gotten better at writing these kinds of tests, and I think now that the codebase has matured it's time to be more deliberate in our test coverage.

Actionables

• Add coverage report
  • See example patch that did the same thing for a different repo
• Set a minimum coverage threshold
  • If coverage falls below a certain amount, CI builds will fail
• Add snapshot tests
  • These will reinforce visual changes are deliberate.
  • https://doc.wikimedia.org/codex/latest/contributing/contributing-code/testing-components.html#snapshot-tests
  • https://jestjs.io/docs/snapshot-testing
• Add test cases for previously reported bugs and regressions (search query)
• Possibly more Selenium tests (?)
  • These are slow, but are the most definitive for end-to-end user testing
  • We have but one singe test right now that only covers that a block visually succeeded.