Accessing .mock property of an automocked function

Question

I have this code:

import * as a from 'a-a';
jest.mock('a-a');

describe('a-a', () => {
    beforeAll(async () => {
        const x = await a.x(1); // Calls the mock
        console.log(x);   // 1
        console.log(a.x.mock) // Undefined
    });
});

The mock function is:

export async function x(data) {
    cache.push(data);

    console.log('HERE'); // this is printed

    return data;
}

The mock of the module is in the __mocks__ directory.

The a.x() calls the mocked function, but a.x.mock is undefined.

How is that possible? Where is the .mock property?

@AndreasKöberle `[Function: x]`. Maybe relevant, `x` is `async` — rpadovani, Jun 21 '17 at 09:16
Would it be a solution to mock it like this: `jest.mock('a-a', () => ({x: jest.fn()}))` . Its a bit more to write but at least this will work. — Andreas Köberle, Jun 21 '17 at 09:21
I also wonder how your example works, cause I thought it would mock the module with a function that returns `undefined`. — Andreas Köberle, Jun 21 '17 at 09:22
@AndreasKöberle I'd prefer to have the automock. No the mocked function actually return something, I updated the question — rpadovani, Jun 21 '17 at 09:34
@AndreasKöberle it is already in the question, I updated before :) — rpadovani, Jun 21 '17 at 11:53

score 0 · Accepted Answer · answered Jun 23 '17 at 15:45

So, after some investigation I found out that the functions declared in the __mocks__ directory aren't wrapped by jest.fn() by default.

Personally I find the thing a bit confusing.

So you can do both

function x(data) {
    cache.push(data);

    return cache;
}

jest.mock('a-a', () => ({x: x}))

if you do everything in the same file, or

jest.mock('a-a');

and then in the __mocks__/a-a.js file

export const x = jest.fn(async (data) => {
    cache.push(data);

    return cache;
});

Accessing .mock property of an automocked function

1 Answers1