CODEWITHSUNDEEP
reactjsunit-testingmockingjestjsreact-testing-library
Stanila Andrei
Stanila Andrei

Reputation: 55

How do I mock firebase analitycs with jest?

I have a component that use firebase.analytics() and I try to mock it.

//__mocks__/firebase/app.mocks.ts   
export const analytics = jest.fn();

And I get an error when is trying to call it like this on the second line:

firebase.initializeApp(clientCredentials);
firebase.analytics();

The error is TypeError: _app.default.analytics is not a function

Used jest to mock these like this:

jest.mock('firebase/app');
jest.mock('firebase/analytics');

I should do something more?

Upvotes: 1

Views: 2438

Answers (1)

Lin Du
Lin Du

Reputation: 102207

Here is an example only using jest.mock(moduleName, factory, options) method without creating __mocks__ directory.

index.ts:

import firebase from 'firebase';

function main() {
  const clientCredentials = {};
  firebase.initializeApp(clientCredentials);
  firebase.analytics();
}

export { main };

index.test.ts:

import { main } from './';
import firebase from 'firebase';

jest.mock('firebase', () => {
  return { initializeApp: jest.fn(), analytics: jest.fn() };
});

describe('63008620', () => {
  afterAll(() => {
    jest.resetAllMocks();
  });
  it('should pass', () => {
    main();
    expect(firebase.initializeApp).toBeCalledWith({});
    expect(firebase.analytics).toBeCalledTimes(1);
  });
});

unit test result:

 PASS  stackoverflow/63008620/index.test.ts (14.665s)
  63008620
    ✓ should pass (7ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |     100 |      100 |     100 |     100 |                   
 index.ts |     100 |      100 |     100 |     100 |                   
----------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        16.565s

Upvotes: 2

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