TMEDIA-580 test only changed files on push and in actions

[JackHowa]

Description

Test locally only changed files on push* to improve dev productivity

Jira Ticket

• TMEDIA-580

Acceptance Criteria

• On developer push locally, testing should only occur on files that changed vs canary base branch
• GitHub Actions run on changed as well rather than all of the tests on prs to canary only

Test Steps

1. Checkout this branch git checkout TMEDIA-580-test-commit-changed
2. Reinstall your deps rm -rf node_modules && npm i for new jest version
3. In one file, like byline, break the tests: const ArticleByline = () => <Byline font="Primary" />; -> const ArticleByline = () => <p>by</p>;
4. stage the file git add blocks/byline-block/features/byline/default.jsx
5. Commit the file git commit -m "only byline"
6. Break the tests of another file
7. Add the file and commit the file
8. Try to git push. See the linting run (deferred to future ticket). See the only files changed are being tested. This should fail
9. To reset your branch to mine, run git reset --hard origin/TMEDIA-580-test-commit-changed

Effect Of Changes

Before

• On push, every test is run, taking minutes
• Github actions test take a long time

After

• On push, only relevant files are tested, taking seconds (depending on how many files changed)
• Github action testing speed is improved as well
• See github action running and failing with two commits on files https://github.com/WPMedia/arc-themes-blocks/runs/4707169538?check_suite_focus=true
• See passing github action https://github.com/WPMedia/arc-themes-blocks/runs/4731349155?check_suite_focus=true

Dependencies or Side Effects

• I removed the output type-specific coverage as new code there will require high code coverage anyway. Also, I didn't want to diverge collect coverage didn't seem to work as expected when there were no files changed Coverage data was not found when using "--collectCoverageFrom" jestjs/jest#5580 Do not fail on 'Jest: Coverage data for ... was not found.' or make coverageThreshold configurable on the cli jestjs/jest#8474
• Linting is still on push all files. This will be addressed in the future
• Had to update jest due to a bug with onlyChanged in the GitHub action changedSince runs specs related to files with no diff jestjs/jest#9602
• Only targets the canary branch for changes and tests

Author Checklist

The author of the PR should fill out the following sections to ensure this PR is ready for review.

• Confirmed all the test steps a reviewer will follow above are working.
• Confirmed there are no linter errors. Please run npm run lint to check for errors. Often, npm run lint:fix will fix those errors and warnings. -> na
• Ran this code locally and checked that there are not any unintended side effects. For example, that a CSS selector is scoped only to a particular block. -> na
• Confirmed this PR has reasonable code coverage. You can run npm run test:coverage to see your progress.
  • Confirmed this PR has unit test files
  • Ran npm run test, made sure all tests are passing
  • If the amount of work to write unit tests for this change are excessive,
    please explain why (so that we can fix it whenever it gets refactored). -> na
• Confirmed relevant documentation has been updated/added.

Reviewer Checklist

The reviewer of the PR should copy-paste this template into the review comments on review.

• Linting code actions have passed.
• Ran the code locally based on the test instructions.
  • I don’t think this is needed to be tested locally. For example, a padding style change (storybook?) or a logic change (write a test).
• I am a member of the engine theme team so that I can approve and merge this. If you're not on the team, you won't have access to approve and merge this pr.
• Looked to see that the new or changed code has code coverage, specifically. We want the global code coverage to keep on going up with targeted testing.

[matthewroach]

Couple of small name changes to remove "news theme" references

[JackHowa]

Good call @matthewroach -- updated