I have a CRA-rewired typescript react app.

Jest is imported globally.

In order to use jest mocks I have to write

jest.mock('module-name') ABOVE describe() block and IN THE same file, e.g.

import { act, render, screen } from '@testing-library/react';
import { MyComponent } from './MyComponent';
import { something } from 'my-module';

jest.mock('my-module');

describe('MyComponent', () => {
    afterAll(() => {
        jest.unmock('my-module');
    });

    afterEach(() => {
        jest.resetAllMocks();
        jest.useRealTimers();
    });

    test('component renders', async () => {
        (something as jest.MockedFunction<typeof something>).mockImplementation(() => 'banana');
        const { container } = render(<MyComponent></MyComponent>);
        expect(screen.queryByText('banana')).toBeVisible();
    });
});

Now I have a few hundred test suites and thousands of tests.

Some of them have COMMON things I want to mock (like my-module), but not ALL.

So I don’t want to use testSetup.js to mock the modules in ALL tests, but I DO WANT to find a way to not have to write jest.mock() over and over again.

So I tried creating a utilities module like so:

const TestUtilities = {
    mockMyModule: () => {
        jest.mock('my-module');
    },

    unmockMyModule: () => {
        jest.unmock('my-module');
    },
};

export default TestUtilities;

and then modified the original test:

import { act, render, screen } from '@testing-library/react';
import { MyComponent } from './MyComponent';
import { something } from 'my-module';
import TestUtilities from './TestUtilities';

TestUtilities.mockMyModule();

describe('MyComponent', () => {
    afterAll(() => {
        TestUtilities.unmockMyModule();
    });

    afterEach(() => {
        jest.resetAllMocks();
        jest.useRealTimers();
    });

    test('component renders', async () => {
        (something as jest.MockedFunction<typeof something>).mockImplementation(() => 'banana');
        const { container } = render(<MyComponent></MyComponent>);
        expect(screen.queryByText('banana')).toBeVisible();
    });
});

Unfortunately now test behaves as if my-module is not mocked 🙁

Is there a way to re-use those jest.mock() blocks?