Description

The following changes were applied in this PR:

• The bundled jest dependency has been updated from requiring ^23.6.0 to requiring ^24.1.0 (see Braking Changes.
• The bundled jest-puppeteer dependency has been updated from requiring 3.2.1 to requiring ^4.0.0.
• The bundled puppeteer dependency has been updated from requiring 1.6.1 to requiring ^1.12.2. - it looks like such upgrade on its own breaks our e2e tests ...
• The bundled jest-enzyme dependency has been removed completely (it doesn't work with Jest 24 and we rather sunset support for Enzyme one day than continue to suffer keeping it up to date).
• The bundled enzyme dependency has been updated from requiring ^3.7.0 to requiring ^3.9.0.
• Removed babel-core dependency acting as Babel 7 bridge (no longer needed by Jest 24).

The biggest internal change caused by Jest upgrade was the need to replace usage of setupTestFrameworkScriptFile with setupFilesAfterEnv. Otherwise, as noted above, I had to remove jest-enzyme dependency and therefore update a few assertions which were using custom matchers.

There are 3 packages which were also updated but they weren't published to npm so far so I didn't update the corresponding changelog files:

• jest-puppeteer-axe
• e2e-test-utils
• e2e-tests

How has this been tested?

npm test
npm run test-e2e

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.