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I am trying to mock history.push inside the new useHistory hook on react-router and using @testing-library/react. I just mocked the module like the first answer here: How to test components using new react router hooks?

So I am doing:

//NotFound.js
import * as React from 'react';
import { useHistory } from 'react-router-dom';


const RouteNotFound = () => {
  const history = useHistory();
  return (
    <div>
      <button onClick={() => history.push('/help')} />
    </div>
  );
};

export default RouteNotFound;

//NotFound.test.js
describe('RouteNotFound', () => {
  it('Redirects to correct URL on click', () => {
    const mockHistoryPush = jest.fn();

    jest.mock('react-router-dom', () => ({
      ...jest.requireActual('react-router-dom'),
      useHistory: () => ({
        push: mockHistoryPush,
      }),
    }));

    const { getByRole } = render(
        <MemoryRouter>
          <RouteNotFound />
        </MemoryRouter>
    );

    fireEvent.click(getByRole('button'));
    expect(mockHistoryPush).toHaveBeenCalledWith('/help');
  });
})

But mockHistoryPush is not called... What am I doing wrong?

Answers

You actually do not need to mock react-router-dom (at least for v5) as it provides a bunch of testing tools: https://v5.reactrouter.com/web/guides/testing

To check your history is actually changed, you can use createMemoryHistory and inspect its content:

import React from 'react';
import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { Menu } from './Menu';
import { createMemoryHistory } from 'history'
import { Router } from 'react-router-dom';

test('triggers path change', () => {
  const history = createMemoryHistory();

  render(
    <Router history={history}>
      <Menu />
    </Router>
  );

  const aboutItem = screen.getByText('About');
  expect(aboutItem).toBeInTheDocument();

  userEvent.click(aboutItem);
  expect(history.length).toBe(2);
  expect(history.location.pathname).toBe('/about');
});