Simple extension of the default Jest runner that makes it run serially (as of running with --runInBand flag) The non-cli functionality is slightly hidden in the Jest docs.
Useful for integration tests.
npm install @ethersphere/jest-serial-runner --save-dev
"runner": "@ethersphere/jest-serial-runner" in your jest config
Credit to @codejedi365 and @gabrieli that developed the original solution.