Jest, Enzyme: Invariant Violation: You should not

Question

I have a <UserListComponent /> which outputs one <Contact /> component and list of contacts presentated by <Contacts />.

The problem is that in the test for <UserListComponent /> when I try to mount it, test outputs an error Invariant Violation: You should not use <Route> or withRouter() outside a <Router>

withRouter() is used in <Contacts /> component.

How can I mock ContactsComponent without router in test of parent component?

I found some similar issue https://www.bountysource.com/issues/49297944-invariant-violation-you-should-not-use-route-or-withrouter-outside-a-router but it only describes situation when component is cover by withRouter() itself, not children.

UserList.test.jsx

const mockResp = {
  count: 2,
  items: [
    {
      _id: 1,
      name: 'User1',
      email: '[e-mail]',
      phone: '+123456',
      online: false
    },
    {
      _id: 2,
      name: 'User2',
      email: '[e-mail]',
      phone: '+789123',
      online: false
    },
    {
      _id: 3,
      name: 'User3',
      email: '[e-mail]',
      phone: '[phone]',
      online: false
    }
  ],
  next: null
}

describe('UserList', () => {
  beforeEach(() => {
    fetch.resetMocks()
  });

  test('should output list of users', () => {
    fetch.mockResponseOnce(JSON.stringify(mockResp));

    const wrapper = mount(<UserListComponent user={mockResp.items[2]} />);

    expect(wrapper.find('.contact_small')).to.have.length(3);
  });

})

UserList.jsx

export class UserListComponent extends PureComponent {
  render() {
    const { users, error } = this.state;
    return (
      <React.Fragment>
        <Contact
          userName={this.props.user.name}
          content={this.props.user.phone}
        />
        {error ? <p>{error.message}</p> : <Contacts type="contactList" user={this.props.user} contacts={users} />}
      </React.Fragment>
    );
  }
}

Contacts.jsx

class ContactsComponent extends Component {
  constructor() {
    super();
    this.state = {
      error: null,
    };
  }

  render() {
    return (
      <React.Fragment>
        <SectionTitle title="Contacts" />
        <div className="contacts">
         //contacts
        </div>
      </React.Fragment>
    );
  }
}

export const Contacts = withRouter(ContactsComponent);

Answer 1

You need to wrap the App with a BrowserRouter or an equivalent, see the below example of simple test case a component App that uses React Router

import React from "react";
import ReactDOM from "react-dom";
import { BrowserRouter } from "react-router-dom";
import App from "./App";

it("renders without crashing", () => {
  const div = document.createElement("div");
  ReactDOM.render(
<BrowserRouter>
  <App />
</BrowserRouter>,
div
  );
  ReactDOM.unmountComponentAtNode(div);
})

Answer 2

To test a component (with Jest) that contains <Route> and withRouter you need to import Router in you test, not in your component

import { BrowserRouter as Router } from 'react-router-dom';

and use it like this

app = shallow(
    <Router>
        <App />
    </Router>);

Answer 3

Utility Function To Wrap Mount With Context

Wrapping mount with Router in tests works, but there are situations where you don't want Router to be the parent component in your mount. Therefore I'm currently injecting context into mount using a wrapper function:

import { BrowserRouter } from 'react-router-dom';
import Enzyme, { shallow, mount } from 'enzyme';

import { shape } from 'prop-types';

// Instantiate router context
const router = {
  history: new BrowserRouter().history,
  route: {
    location: {},
    match: {},
  },
};

const createContext = () => ({
  context: { router },
  childContextTypes: { router: shape({}) },
});

export function mountWrap(node) {
  return mount(node, createContext());
}

export function shallowWrap(node) {
  return shallow(node, createContext());
}

This could be in a file called, say contextWrap.js, in a test helpers directory.

Example describe block:

import React from 'react';
import { TableC } from '../../src/tablec';
import { mountWrap, shallowWrap } from '../testhelp/contextWrap';
import { expectedProps } from './mockdata'

describe('Table', () => {
  let props;
  let component;
  const wrappedShallow = () => shallowWrap(<TableC {...props} />);

  const wrappedMount = () => mountWrap(<TableC {...props} />);

  beforeEach(() => {
    props = {
      query: {
        data: tableData,
        refetch: jest.fn(),
      },
    };
    if (component) component.unmount();
  });

  test('should render with mock data in snapshot', () => {
    const wrapper = wrappedShallow();
    expect(wrapper).toMatchSnapshot();
  });

  test('should call a DeepTable with correct props', () => {
    const wrapper = wrappedMount();
    expect(wrapper.find('DeepTable').props()).toEqual(expectedProps);
  });

});

You can also use this pattern to wrap subcomponents in other types of context, for example if you are using react-intl, material-ui or your own context types.

Answer 4

A keeps the history of your "URL" in memory (does not read or write to the address bar). Useful in tests and non-browser environments like React Native.

I got similar error solution is wrapping component with the help of Memory router

import { MemoryRouter } from 'react-router'

<MemoryRouter>
  <App/>
</MemoryRouter>

Answer 5

i had same problem, and first comment helped me, but there are a lot of code i have better way how to resolve this problem. See my solution below:

    import React from 'react';
import { shallow, mount } from 'enzyme';
import SisuSignIn from '../../../components/Sisu/SisuSignIn.js';
import { MemoryRouter } from 'react-router-dom';

const Container = SisuSignIn;

let wrapper;

beforeEach(() => {
  wrapper = shallow(<Container />);
});

describe('SisuSignIn', () => {
  it('renders correctly', () => {
    expect(wrapper).toMatchSnapshot();
  });
  it('should render one <h1>', () => {
    const wrapper = mount(
      <MemoryRouter>
        <SisuSignIn auth={{ loading: false }} />
      </MemoryRouter>
    );
    expect(wrapper.find('div').length).toBe(12);
  });
});