Enzyme: Enzyme does not call useEffect with update() on wrapper created via mount

Created on 4 Oct 2019 · 5Comments · Source: enzymejs/enzyme

Current behavior

useEffect is not called on wrapper.update() (wrapper created via mount).

Expected behavior

I would expect useEffect to be called in this situation. As a workaround, I am using setProps() instead of update()

Your environment

OS X 10.14.5

API

[ ] shallow
[x] mount
[ ] render

Version

| library | version
| ------------------- | -------
| enzyme | 3.10.0
| react | 16.9.0
| react-dom | 16.9.0
| react-test-renderer | 16.9.0
| adapter (below) | 1.14.0

Adapter

[x] enzyme-adapter-react-16
[ ] enzyme-adapter-react-16.3
[ ] enzyme-adapter-react-16.2
[ ] enzyme-adapter-react-16.1
[ ] enzyme-adapter-react-15
[ ] enzyme-adapter-react-15.4
[ ] enzyme-adapter-react-14
[ ] enzyme-adapter-react-13
[ ] enzyme-adapter-react-helper
[ ] others ( )

Example Code

App.js

import React from 'react';

export default function App() {
  React.useEffect( () => {} );
  return <div />;
}

App.test.js

import React from 'react';
import Enzyme, { mount } from 'enzyme';
import App from './App';
import EnzymeAdapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new EnzymeAdapter() });

test("useEffect is called on update", () => {
  const mockUseEffect = jest.fn();
  React.useEffect = mockUseEffect;

  const wrapper = mount(<App />);

  mockUseEffect.mockClear();
  wrapper.update();

  expect(mockUseEffect).toHaveBeenCalled();
});

If I replace wrapper.update() with wrapper.setProps(), the test passes.

Source

bonnie

👍5

Most helpful comment

Ah - wrapper.update() does not force a rerender, so you'd need something like setProps to force that. You could also use, say, useState inside App and setState inside the component, forcing a rerender, and I'd expect it to run then as well.