How to test a function call inside another function? JEST-CodePudding

In case you're interested, I solved this already using the first solution provided. I was missing babel from jest, I was using the experimental es6 settings found in jest documentation stating I should remove the transformation, add test node --experimental-vm-modules node_modules/jest/bin/jest.js, etc. Not really sure what is that for, I thought it was for this very thing but apparently not.

I've read many posts here and tried many solutions but nothing seems to work for me, how can I test in Jest that the calling function is being called inside init?

Here's what I have:

calling.js

const calling = () => {
  return 'calling';
};

export default calling;

init.js

import calling from './calling';

export const init = () => {
  calling();
};

test.spec.js

import { jest } from '@jest/globals';
import init from './init.js';
import calling from './calling.js';

test('init calls calling', () => {
  // what to do here?
});

package.json

{
  "name": "testing",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js"
  },
  "type": "module",
  "jest": {
    "transform": {},
    "roots": [
      "<rootDir>"
    ],
    "modulePaths": [
      "<rootDir>"
    ],
    "moduleDirectories": [
      "node_modules"
    ]
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/jest": "^28.1.8",
    "jest": "^28.1.3"
  }
}
};

It kind of work now based on the solution provided above BUT! I have to do a more complicated setup in order to work and I can't figure out why. Also, I had to do name exports because it doesn't work with default export and I can't figure out how to do it either.

import { jest } from '@jest/globals';

const mock = jest.fn();

jest.unstable_mockModule('./calling.js', () => ({
  calling: mock,
}));

const { calling } = await import('./calling.js');
const { init } = await import('./init.js');

test('test', async () => {
  init();
  expect(calling).toHaveBeenCalled();
});

CodePudding user response：

In this case, you can simply use the Jest autoMocking function and verify whether it actually been called

// test.spec.js
import { init } from './init';
import calling from './calling';

jest.mock('./calling');

test('init calls fn calling', () => {
  init();
  expect(calling).toHaveBeenCalled();
});

I assume it did not work out for you because you have a mistake in importing

import init from './init.js'; // not default export
// should be
import {init} from './init.js';