JestJS - Trying to Mock Async Await in Node JS Tests
16,440
You should be careful about somethings below:
Import your
utils
as a module then mockcallAnotherLambdaFunction
functionMock return value of
callAnotherLambdaFunction
withResolve
andReject
case https://jestjs.io/docs/en/mock-function-api.html#mockfnmockresolvedvaluevalue
This is my example:
import testData from '../data.js';
import { handler } from '../src/index.js';
import * as Utils from '../../../utils'
jest.mock('../../../utils');
beforeAll(() => {
Utils.callAnotherLambdaFunction = jest.fn().mockResolvedValue('test');
});
describe('>>> SEND EMAIL LAMBDA', () => {
it('should return a good value', async () => {
const callback = jest.fn()
await handler(testData, null, callback);
expect(callback).toBeCalledWith(null, {success: true, returnValue: 'test'})
});
})
Author by
andre
Updated on June 20, 2022Comments
-
andre almost 2 years
I am attempting to use Jest for my Node Js Test (specifically AWS's Lambda) but I am having difficulty mocking async await functionality.
I am using babel-jest and jest-cli. Below are my modules. I am getting to the first console.log, but the second console.log returns undefined and my test crash.
Any ideas on how to implement this?
Below is my module:
import {callAnotherFunction} from '../../../utils'; export const handler = async (event, context, callback) => { const {emailAddress, emailType} = event.body; console.log("**** GETTING HERE = 1") const sub = await callAnotherFunction(emailAddress, emailType); console.log("**** Not GETTING HERE = 2", sub) // **returns undefined** // do something else here callback(null, {success: true, returnValue: sub}) }
My Test
import testData from '../data.js'; import { handler } from '../src/index.js'; jest.mock('../../../utils'); beforeAll(() => { const callAnotherLambdaFunction= jest.fn().mockReturnValue(Promise.resolve({success: true})); }); describe('>>> SEND EMAIL LAMBDA', () => { test('returns a good value', done => { function callback(dataTest123) { expect(dataTest123).toBe({success: true, returnValue: sub); done(); } handler(testData, null, callback); },10000); })