dooms-day mockery.js

dooms-day.test.js

import mockery from 'mockery';
import sinon from 'sinon';
//import {Launch} from './rocket-silo'; // you cannot use imports
//import {theDay} from 'doom-scheduler'

mockery.registerMock('./rocket-silo', {
 Launch: sinon.stub()
});

mockery.registerMock('doom-scheduler', {
 theDay: Promise.resolve()
});

mockery.enable();
const {Launch} = require('./rocket-silo');
mockery.disable();

expect(Launch).toHaveBeenCalled();