Marry Jest with CircleCI with some bonuses.

Problem: I want to run Jest tests on CircleCI. I have got many tests and I am on the free tier of CircleCI. Why is it a problem? Because Jest runs tests in parallel and I got “Out of memory” from CircleCI.

Solution: Add maxWorkers parameter to Jest.

-- --maxWorkers=4

Bonus #1: To get code coverage report from Jest

-- --coverage

Bonus #2: To fail Jest run when the first test fails

-- --bail

Bonus #3: To flush AWS Gateway API authorizer

aws apigateway flush-stage-authorizers-cache --rest-api-id ${apiId} --stage-name ${stage}