Jest Coverage Validator

Validates Jest test coverage thresholds to be sure your coverage doesn't decrease. Executes a supplied fail (and optional pass) function after coverage is checked.

Use this during CI or other build processes.

Use it alongside something like jest-coverage-ratchet.

How it works

Two jest-cli commands are ran:

• jest --coverage --json
• jest --showConfig --json

The results are compared against the global thresholds in your Jest config (probably in your package.json) to see if your thresholds are not met.

Simple API

Pass in a fail function to validate to:

• Fail a build
• Send a Slack message
• Etc.

Args:

• fail is called with a list of failed thresholds.
• pass is called with true if no thresholds fail. Optional.

// circle.yml
...
dependencies:
  cache_directories:
    - ~/.yarn-cache
  override:
    - yarn
    - yarn test
    - node ./ci-coverage-validate.js
    - yarn build
    - docker info
...

// ci-coverage-validate.js
const validate = require('jest-coverage-validator').validate;

function fail (failures) {
    global.console.error('Code coverage does not meet minimum threshold.');
    global.console.error('Failures: ', failures);
    process.exit(1);
}

function pass () {
    global.console.log('Yay, code coverage didn\'t go down!');
    process.exit(0);
}

validate(fail, pass);