Debugging jest tests with breakpoints.

Place a debugger; statement in any of your tests. Then when running the test suite use the --inspect-brk flag.

node --inspect-brk node_modules/.bin/jest --runInBand [any other arguments]

To debug in Google Chrome (or any Chromium-based browser), open your browser and go to chrome://inspect and click on "Open Dedicated DevTools for Node".

Source