Testing Hooks with shallow: Invariant Violation #1938

TdyP · 2018-12-11T11:02:18Z

Current behavior

When testing component which contains newly released React Hooks using shallow, it crashes:
Invariant Violation: Hooks can only be called inside the body of a function component.

Everything works fine at run time or when testing with render:

My test component:

import * as React from 'react';

function Test() {
    const [myState, setMyState] = React.useState('Initial state');

    const changeState = () => setMyState('State updated');

    return (
        <div>
            {myState}
            <button onClick={changeState}>Change</button>
        </div>
    );
}

export default Test;

My test file:

import { shallow } from 'enzyme';
import * as React from 'react';
import Test from './Test';

it('renders without crashing', () => {
    const comp = shallow(<Test />);

    expect(comp.find('Test')).toMatchSnapshot();
});

Error stack trace:

Invariant Violation: Hooks can only be called inside the body of a function component.

    at invariant (node_modules/react/cjs/react.development.js:125:15)
    at resolveDispatcher (node_modules/react/cjs/react.development.js:1450:28)
    at Object.useState (node_modules/react/cjs/react.development.js:1473:20)
    at Test (src/Test.tsx:4:11)
    at node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:440:38
    at ReactShallowRenderer.render (node_modules/react-test-renderer/cjs/react-test-renderer-shallow.development.js:412:39)
    at node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:444:37
    at withSetStateAllowed (node_modules/enzyme-adapter-utils/build/Utils.js:137:16)
    at Object.render (node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:443:70)
    at new ShallowWrapper (node_modules/enzyme/build/ShallowWrapper.js:206:22)
    at Object.shallow (node_modules/enzyme/build/shallow.js:21:10)
    at Object.<anonymous> (src/Test.test.tsx:6:18)
        at new Promise (<anonymous>)
    at Promise.resolve.then.el (node_modules/p-map/index.js:46:16)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Expected behavior

Tests should run

Your environment

Fresh create-react-app-typescript install with react 16.7.0-alpha-0

API

shallow
mount
render

Version

library	version
enzyme	3.8.0
react	16.7.0-alpha.0
react-dom	16.7.0-alpha.0
react-test-renderer
adapter (below)

Adapter

The text was updated successfully, but these errors were encountered:

ljharb · 2018-12-12T08:39:36Z

Hooks are not yet in a non-alpha version, and are definitely not yet supported in enzyme.

I'd suggest waiting to use them until they're not experimental.

oliviertassinari · 2018-12-15T15:27:45Z

@ljharb Hooks are labeled "upcoming" now 🤔.

ljharb · 2018-12-15T16:37:08Z

Fair enough, but they’re still both not yet a thing in a real version, and enzyme doesn’t yet have support for them.

juniusfree · 2019-01-08T16:04:14Z

An open issue in react facebook/react/#14091

juniusfree · 2019-01-19T07:32:54Z

An open issue in react facebook/react/#14091

Merged at facebook/react#14567

ljharb · 2019-01-24T00:39:30Z

Reopening, since facebook/react#14679 is now merged and v16.8 seems imminent.

Also tracked in #1553.

chenesan · 2019-01-24T02:42:47Z

@ljharb I'd love to help to look into what we need to do to support hooks after v16.8 release.
Also note that in facebook/react#14567 the shallow renderer will support hooks, so maybe there won't be too much work in enzyme.

ljharb · 2019-01-24T03:44:24Z

@chenesan that would be great. The biggest priority is getting as many tests as possible, and mirroring those as much as possible between shallow and mount.

joshnabbott · 2019-02-07T01:19:58Z

Hooks have been released and this still seems to be an issue with enzyme's shallow renderer. Is there any sort of ETA on getting an update to enzyme to support hooks?

chenesan · 2019-02-07T01:26:34Z

I don't know if there's any ETA for supporting hooks but I'll start to work on this in recent days :-)

ljharb · 2019-02-07T02:52:17Z

If it’s still an issue with every React package (including the test renderer) at 16.8, then a PR with tests would be quite welcome.

wodenx · 2019-02-07T03:30:09Z

I am having a possibly related issue with 16.8. I don't get the Invariant Violation, but some hooks which persist data across renders (useRef and useState) are not behaving as expected during shallow render, but work fine during mount.

Versions:

├─ enzyme-adapter-react-16@1.9.1
├─ enzyme@3.8.0
├─ jest@23.6.0
├─ react-dom@16.8.1
└─ react@16.8.1

Tests:

import * as React from 'react';
import { shallow, mount } from 'enzyme';

class ClassInstance extends React.Component {
  constructor(props) {
    super(props);
    this.id = Math.random().toString();
  }

  render() {
    return <div>{this.id}</div>;
  }
}

const SFCRef = () => {
  const id = React.useRef(Math.random().toString());
  return <div>{id.current}</div>;
};

const SFCState = () => {
  const [id] = React.useState(Math.random().toString());
  return <div>{id}</div>;
};

test('1 class instance property persists with shallow', () => {
  const wrapper = shallow(<ClassInstance foo="a" />);
  const id = wrapper.text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.text();
  expect(id).toBe(id1);
});

test('2 class instance property persists with mount', () => {
  const wrapper = mount(<ClassInstance foo="a" />);
  const id = wrapper.find('div').text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.find('div').text();
  expect(id).toBe(id1);
});

test('3 SFC ref persists with mount', () => {
  const wrapper = mount(<SFCRef foo="a" />);
  const id = wrapper.find('div').text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.find('div').text();
  expect(id).toBe(id1);
});

test('4 SFC ref persists with shallow', () => {
  const wrapper = shallow(<SFCRef foo="a" />);
  const id = wrapper.text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.text();
  expect(id).toBe(id1);
});

test('5 SFC state persists with mount', () => {
  const wrapper = mount(<SFCState foo="a" />);
  const id = wrapper.find('div').text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.find('div').text();
  expect(id).toBe(id1);
});

test('6 SFC state persists with shallow', () => {
  const wrapper = shallow(<SFCState foo="a" />);
  const id = wrapper.text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.text();
  expect(id).toBe(id1);
});

// Verify that an id which *should not* persist across renders in fact does not.
const SFC = () => {
  const id = Math.random().toString();
  return <div>{id}</div>;
}

test('7 SFC alone does not persist with mount', () => {
  const wrapper = mount(<SFC foo="a" />);
  const id = wrapper.find('div').text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.find('div').text();
  expect(id).not.toBe(id1);
});

test('8 SFC alone does not persist with shallow', () => {
  const wrapper = shallow(<SFC foo="a" />);
  const id = wrapper.text();
  wrapper.setProps({ foo: 'b' });
  const id1 = wrapper.text();
  expect(id).not.toBe(id1);
});

Results:

  ✓ 1 class instance property persists with shallow (8ms)
  ✓ 2 class instance property persists with mount (31ms)
  ✓ 3 SFC ref persists with mount (3ms)
  ✕ 4 SFC ref persists with shallow (11ms)
  ✓ 5 SFC state persists with mount (2ms)
  ✕ 6 SFC state persists with shallow (2ms)
  ✓ 7 SFC alone does not persist with mount (3ms)
  ✓ 8 SFC alone does not persist with shallow

ljharb · 2019-02-07T03:34:03Z

@wodenx what version of react-test-renderer do you have?

wodenx · 2019-02-07T04:07:28Z

@ljharb lol i was just checking that - i just upgraded from 16.8.0 to 16.8.1 and have the same results.

icyJoseph · 2019-02-12T08:48:07Z

Has anyone managed to pull out a magic trick to use Hooks, with Enzyme, shallow or mount?

TdyP · 2019-02-12T10:08:48Z

@icyJoseph I managed to get this working by upgrading everything around react and testing:

"enzyme": "3.8.0"
"enzyme-adapter-react-16": "1.9.1",
"react": "16.8.1",
"react-dom": "16.8.1",
"react-test-renderer": "16.8.1",

icyJoseph · 2019-02-12T10:59:58Z

@TdyP I have all of those libraries updated, and still I cannot get a simple toggle to work.

In your example at the top, how do you trigger the state change when using the onClick prop?

I target the prop and call the function attached to it, using the act helper, but the state does not update.

TdyP · 2019-02-12T13:09:13Z

@icyJoseph Here's a working example with mount. Didn't manage to get it working with shallowactually

The component Test.tsx

import * as React from 'react';

function Test() {
    const [myState, setMyState] = React.useState('initial_state');

    const changeState = () => setMyState('updated_state');

    return (
        <div>
            <div className="stateContent">{myState}</div>
            <button onClick={changeState}>Change</button>
        </div>
    );
}

export default Test;

Test file Test.test.tsx

import { mount } from 'enzyme';
import * as React from 'react';
import Test from './Test';

it('renders without crashing', () => {
    const comp = mount(<Test />);

    comp.find('button').simulate('click');

    expect(comp.find('div.stateContent').text()).toBe('updated_state');
});

Hope this helps!

stringerbell · 2019-02-14T20:35:35Z

This works for now. You need to add react-test-renderer if it's not already a dependency.


const ComponentWithHooks = () => {
  const [count, setCount] = useState(0);
  return <p onClick={() => setCount(count + 1)}>Count is {count}</p>;
};
describe('ComponentWithHooks', () => {
  it('explodes', () => {
    const wrapper = shallow(<ComponentWithHooks />); // Invariant Violation: Hooks can only be called inside the body of a function component. (https://fb.me/react-invalid-hook-call)
  });

  it("doesn't explode with a workaround", () => {
    const renderer = new ShallowRenderer();
    renderer.render(<ComponentWithHooks />);
    const output = renderer.getRenderOutput();
    const wrapper = shallow(<div>{output}</div>); // Have to wrap it, otherwise you get: TypeError: ShallowWrapper can only wrap valid elements
    // ...
  });
});

icyJoseph · 2019-02-15T06:45:36Z

This works for now. You need to add react-test-renderer if it's not already a dependency.


const ComponentWithHooks = () => {
  const [count, setCount] = useState(0);
  return <p onClick={() => setCount(count + 1)}>Count is {count}</p>;
};
describe('ComponentWithHooks', () => {
  it('explodes', () => {
    const wrapper = shallow(<ComponentWithHooks />); // Invariant Violation: Hooks can only be called inside the body of a function component. (https://fb.me/react-invalid-hook-call)
  });

  it("doesn't explode with a workaround", () => {
    const renderer = new ShallowRenderer();
    renderer.render(<ComponentWithHooks />);
    const output = renderer.getRenderOutput();
    const wrapper = shallow(<div>{output}</div>); // Have to wrap it, otherwise you get: TypeError: ShallowWrapper can only wrap valid elements
    // ...
  });
});

I think, the invariant problem goes away if you just change that arrow function in ComponentWithHooks for a regular JS function. The problem comes down the line in the testing because shallow rendered components do not update the state through the hooks. Only mount does that.

stringerbell · 2019-02-15T13:36:33Z

@icyJoseph ah gotcha -- I misunderstood what was wanted based on the invariant violation issue in here (and what I was running into)

bdwain · 2019-03-31T01:39:30Z

I created a react issue for this

koszatnik12 · 2019-04-03T09:07:32Z

@bdwain Hi :)
You wrote, that you've been able to run a simple test with useState, I've alse written one simple case and unfortunately it did not work. Maybe you know what is wrong here or maybe it is some React bugs - I am not sure, and I don't want to create new issue if it is only my mystake

   import React, { useState } from 'react';

    const TestComponent = () => {
        const [myState, setMyState] = useState('1234');

        return (
            <>
                <input onChange={({ target: { value } }) => setMyState(value)} />
                <p>{myState}</p>
            </>
        );
    };
    export { TestComponent };

    describe('Test Copoment', () => {
        it('should change myState value on input change', () => {
            // Given
            const testComponent = shallow(<TestComponent />);
            const { onChange } = testComponent.find('input').props();

            // Then 
            expect(testComponent.find('p')).toHaveText('1234');

            // When
            act(() => {
                onChange({ target: { value: '8658' } });
                components.update();
            });

            // Then 
            expect(testComponent.find('p')).toHaveText('8658');
        });
    });

// Text is still 1234 (initial state)

palaniichukdmytro · 2019-04-03T10:00:48Z

@koszatnik12 I have the same, with enzyme. I updated to lates 16.8.5 but simple unit test with useState does not work for me.

ljharb · 2019-04-03T15:43:30Z

@koszatnik12 there’s a few unreleased changes that might address your problem, but also, there’s no components defined in your example. If you’re still having trouble after the next release, please file a new issue.

alexanderkjeldaas · 2019-04-11T09:31:13Z

@ljharb which release is that?

ljharb · 2019-04-11T23:16:04Z

@alexanderkjeldaas the next one.

kamyaD · 2019-04-13T12:41:11Z

Updating everything solved the problem for me:
"devDependencies": { "enzyme": "^3.9.0", "enzyme-adapter-react-16": "^1.4.0", "eslint": "^5.16.0", "react": "^16.8.6", "react-dom": "^16.8.6", "react-test-renderer": "^16.6.2" }

yuritoledo · 2019-04-21T18:01:55Z

any update?

0xdevalias · 2019-04-24T03:00:41Z

I know it's been said a number of times above, but the main part of the suggested solutions for me was to force yarn to force the resolution of react-test-renderer to match my react version:

https://yarnpkg.com/lang/en/docs/selective-version-resolutions/#toc-how-to-use-it

So I basically ended up with:

..snip..
"dependencies": {
    "react": "^16.8.6",
    "react-dom": "^16.8.6",
    "enzyme": "^3.9.0",
    "enzyme-adapter-react-16": "^1.12.1",
},
"resolutions": {
    "react-test-renderer": "^16.8.6"
  }
}

ljharb · 2019-04-24T03:36:56Z

you don’t even have to do that if your lockfile has the right one.

jnelken · 2019-04-30T21:02:19Z

You can follow the progress here (useEffect with shallow): #2086

yuritoledo · 2019-05-08T01:29:26Z

And about onChange with hooks?

See enzymejs/enzyme#1938.

ljharb · 2019-06-04T00:58:30Z

v3.10.0 has now been released.

EduardoAC · 2019-06-05T08:51:07Z

I am having some trouble to test with shallow render the useState

{
  "jest": "24.8.0",
  "enzyme": "3.10.0",
  "enzyme-adapter-react-16": "1.14.0",
  "enzyme-to-json": "3.3.5",
}

File test is the same used by #1938 (comment)

Happy to raise a new issue if this is not the right place

ljharb · 2019-06-05T15:36:13Z

@EduardoAC a new issue would be very helpful, thanks!

bob-lee · 2019-06-11T00:10:56Z

I had the same issue and the reason was multiple versions of react-test-renderer

$ yarn why react-test-renderer
yarn why v1.16.0
[1/4] Why do we have the module "react-test-renderer"...?
[2/4] Initialising dependency graph...
[3/4] Finding dependency...
[4/4] Calculating file sizes...
=> Found "react-test-renderer@16.8.6"
info Has been hoisted to "react-test-renderer"
info This module exists because it's specified in "dependencies".
=> Found "enzyme-adapter-react-16#react-test-renderer@16.2.0"
info This module exists because "enzyme-adapter-react-16" depends on it.
Done in 1.74s.

For some reason, enzyme-adapter-react-16 had an old react-test-renderer@16.2.0 as its own dependency.
I had to remove and add them back:

yarn remove enzyme enzyme-adapter-react-16 react-test-renderer
yarn add enzyme enzyme-adapter-react-16 react-test-renderer

cagmz · 2019-08-14T16:33:04Z

I was getting intermittent testing failures even after #1938 (comment) . I was able to get my specs passing consistently by doing the following:

yarn upgrade react react-dom --exact
yarn remove enzyme enzyme-adapter-react-16 react-test-renderer
yarn add enzyme enzyme-adapter-react-16 react-test-renderer

Then using Enzyme's mount (instead of shallow) in my failing specs (found after reading this post).

lucasmonteiro001 · 2019-08-31T22:49:36Z

@icyJoseph I managed to get this working by upgrading everything around react and testing:
"enzyme": "3.8.0"
"enzyme-adapter-react-16": "1.9.1",
"react": "16.8.1",
"react-dom": "16.8.1",
"react-test-renderer": "16.8.1",

Thanks a lot @EduardoAC ! It did save me! 😄

joselcc · 2019-10-17T06:20:56Z

updating enzyme-adapter-react-16 to version 1.15.1 fixed the problem for me

EduardoAC · 2019-10-17T07:23:11Z

@lucasmonteiro001 you are very welcome

@joselcc great to hear it

EduardoFLima · 2019-12-04T12:08:44Z

@icyJoseph I managed to get this working by upgrading everything around react and testing:
"enzyme": "3.8.0"
"enzyme-adapter-react-16": "1.9.1",
"react": "16.8.1",
"react-dom": "16.8.1",
"react-test-renderer": "16.8.1",

That worked for me too, thanks !

boda-sh · 2020-02-17T13:39:35Z

This solution worked for us, but we also realised we did not need react-test-renderer at all, so we removed it from package.json completely

yarn remove enzyme enzyme-adapter-react-16 react-test-renderer
yarn add enzyme enzyme-adapter-react-16

Test cases with Hooks still works

ljharb · 2020-02-17T17:49:10Z

@bodazhao it comes along with the react 16 enzyme adapter anyways; but it’s version still needs to be the same minor as react and react-dom.

danielo515 · 2021-05-17T15:57:26Z

This are my dependencies, and I still get this error (hook should not be called outside of balblabla)

    "react": "^16.14.0",
    "react-dom": "^16.13.1",
    "react-test-renderer": "16.14.0",
    "enzyme": "^3.11.0",
    "enzyme-adapter-react-16": "^1.15.2"

Does it matter that between my test file and the inner tested component there is a class based one?
SOmething like this

mount( <Provider><TestedClassComponent/></Provider>

Where TestedClassComponent is a class component that internally uses a functional component that depends on the provider? (which is also functional)

danielo515 · 2021-05-17T16:00:20Z

Does it matter that between my test file and the inner tested component there is a class based one?

I just converted the middle component from class based to functional one and the problem persists.

ljharb closed this as completed Dec 12, 2018

ljharb reopened this Jan 24, 2019

ljharb mentioned this issue Jan 24, 2019

Complete React 16 support #1553

Open

41 tasks

conor-cafferkey-sociomantic mentioned this issue Jan 25, 2019

Convert all components to Hooks sociomantic-tsunami/nessie-ui#766

Closed

35 tasks

xxczaki mentioned this issue Jan 29, 2019

Fix tests pizzaql/pizzaql#3

Closed

This was referenced Feb 7, 2019

[Tests] add hooks tests #2008

Merged

React hooks support checklist #2011

Open

maciossek mentioned this issue Feb 18, 2019

Testing functional components using state hooks with Enzyme reactjs/rfcs#71

Closed

bdwain mentioned this issue May 28, 2019

Feedback needed: add option to enable effects and lifecycle methods in shallow renderer facebook/react#15589

Closed

Christof added a commit to Christof/gql-github that referenced this issue Jun 2, 2019

Recreate yarn.lock to get a single new version of react-test-renderer.

f19b525

See enzymejs/enzyme#1938.

roblevintennis mentioned this issue Aug 13, 2019

File picker component mavenlink/design-system#50

Closed

Aljal mentioned this issue Feb 4, 2020

useEffect not called when the component is shallow renderered #2086

Open

13 tasks

gbonaspetti mentioned this issue Dec 31, 2021

Misc: Update enzyme to have React Hooks support tracim/tracim#5223

Closed

8 tasks

Testing Hooks with shallow: Invariant Violation #1938

Testing Hooks with shallow: Invariant Violation #1938

Comments

TdyP commented Dec 11, 2018 • edited Loading

Current behavior

Expected behavior

Your environment

API

Version

Adapter

ljharb commented Dec 12, 2018

oliviertassinari commented Dec 15, 2018 • edited Loading

ljharb commented Dec 15, 2018

juniusfree commented Jan 8, 2019 • edited Loading

juniusfree commented Jan 19, 2019 • edited Loading

ljharb commented Jan 24, 2019 • edited Loading

chenesan commented Jan 24, 2019

ljharb commented Jan 24, 2019

joshnabbott commented Feb 7, 2019

chenesan commented Feb 7, 2019

ljharb commented Feb 7, 2019

wodenx commented Feb 7, 2019

ljharb commented Feb 7, 2019

wodenx commented Feb 7, 2019

icyJoseph commented Feb 12, 2019

TdyP commented Feb 12, 2019 • edited Loading

icyJoseph commented Feb 12, 2019

TdyP commented Feb 12, 2019

stringerbell commented Feb 14, 2019

icyJoseph commented Feb 15, 2019

stringerbell commented Feb 15, 2019 • edited Loading

bdwain commented Mar 31, 2019

koszatnik12 commented Apr 3, 2019 • edited Loading

palaniichukdmytro commented Apr 3, 2019

ljharb commented Apr 3, 2019

alexanderkjeldaas commented Apr 11, 2019

ljharb commented Apr 11, 2019

kamyaD commented Apr 13, 2019 • edited Loading

yuritoledo commented Apr 21, 2019

0xdevalias commented Apr 24, 2019 • edited Loading

ljharb commented Apr 24, 2019

jnelken commented Apr 30, 2019 • edited Loading

yuritoledo commented May 8, 2019

ljharb commented Jun 4, 2019

EduardoAC commented Jun 5, 2019 • edited Loading

ljharb commented Jun 5, 2019

bob-lee commented Jun 11, 2019

cagmz commented Aug 14, 2019

lucasmonteiro001 commented Aug 31, 2019

joselcc commented Oct 17, 2019

EduardoAC commented Oct 17, 2019

EduardoFLima commented Dec 4, 2019

boda-sh commented Feb 17, 2020

ljharb commented Feb 17, 2020

danielo515 commented May 17, 2021

danielo515 commented May 17, 2021

TdyP commented Dec 11, 2018 •

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oliviertassinari commented Dec 15, 2018 •

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juniusfree commented Jan 8, 2019 •

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juniusfree commented Jan 19, 2019 •

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ljharb commented Jan 24, 2019 •

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TdyP commented Feb 12, 2019 •

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