Jest run async function ONCE before all tests

Question

I want to use jest for my server unit testing (instead of mocha+chai). Is there a way I can run async function before all tests start (init purposes) only once and not for every test file? And also if there's a way of running something after all tests are done?

Answer 1

This feature was added in Jest's 22 version, with globalSetup and globalTeardown configurations. Look at this for examples.

_{package.json (or in jest.config.js)}

{   ...   "jest": {     "globalSetup": "./scripts/jestGlobalSetup.js"   } } 

_{/scripts/jestGlobalSetup.js}

module.exports = async () => {   console.log('\nhello, this is just before tests start running'); }; 

OR

export default async () => {   console.log('\nhello, this is just before tests start running'); };