Testing react router v4 with jest enzyme

Question

I'm trying to do a simple test with react router v4 and jest enzyme.

describe('<App />', () => {

  it('renders a static text', () => {

    const wrapper = shallow(
    <MemoryRouter initialEntries={['/']} initialIndex={0}>
      <App/>
    </MemoryRouter>

    console.log(wrapper.html());
  );

  });
});

When I try to console.log(wrapper.html()), I get:

Invariant Violation: [React Intl] Could not find required `intl` object. <IntlProvider> needs to exist in the component ancestry.

I am using the react-boiler-plate project. All I want to do is test that when I give it a path of '/' then the home page renders some text.

Any help appreciated! Thanks!

EDIT:

This is the test:

it('test', () => {
    const wrapper = shallow(
      <MemoryRouter initialEntries={['/']} initialIndex={0}>
        <Route path="/" render={() => <App/>}/>
      </MemoryRouter>,
    );

    console.log(wrapper.find(App).html());
  });

This is the App class:

export default function App() {
  return (
    <AppWrapper>
      <Helmet
        titleTemplate="%s - React.js Boilerplate"
        defaultTitle="React.js Boilerplate"
      >
        <meta name="description" content="A React.js Boilerplate application"/>
      </Helmet>
      <Header/>
      <Switch>
        <Route exact path="/" component={HomePage}/>
        <Route path="/features" component={FeaturePage}/>
        <Route
          path="/catalog"
          render={() => <div>hi</div>}
        />
        <Route path="" component={NotFoundPage}/>
      </Switch>
      <Footer/>
    </AppWrapper>
  );
}

This is the error message when running the test:

**Error: Method “html” is only meant to be run on a single node. 0 found instead.**

I am expecting that this page would match and I would be able to console.log the output of it:

<Route exact path="/" component={HomePage}/>

Answer 1

Why are you calling console.log inside of shallow? I've never seen this before... Try to wrap your <App /> component in <Route />, and search for some tag inside it. For example. Assuming you have this simple component:

<App>
  <h1>Hi there!</h1>
</App>

Test can look like that:

describe('<App />', () => {

  it('renders a static text', () => {

    const wrapper = shallow(
      <MemoryRouter initialEntries={['/']} initialIndex={0}>
        <Route path="/" render={() => <App />} />
      </MemoryRouter>
    );
    console.log(wrapper.find(App).html());
  });
});

UPDATE It happens that react-boilerplate adds way too much wrappers and dependencies. So for successfull test we need to overcome them in different ways...

This is how I got it done(full content of my react-boilerplate/app/tests/simple.test.js):

import React from 'react';
import { mount } from 'enzyme';
import { MemoryRouter, Route, browserHistory } from 'react-router-dom';
import { IntlProvider } from 'react-intl';
import { Provider } from 'react-redux';

import configureStore from '../configureStore';
import App from '../containers/App';
import { HomePage } from '../containers/HomePage';

describe('test of initial load', () => {
  it('test', () => {
    const store = configureStore({}, browserHistory);
    const wrapper = mount(
      <MemoryRouter initialEntries={['/']} initialIndex={0}>
        <IntlProvider locale="en"> // to add Intl support
          <Provider store={store} > // to provide store for numeric connected components
            <Route path="/" render={() => <App />} />
          </Provider>
        </IntlProvider>
      </MemoryRouter>
    );
    process.nextTick(() => { // to wait for loadible component will be imported
      console.log(wrapper.find(HomePage).html());
    });
  });
});

I think that this is rather integration and not unit test... Output of console.log:

    console.log app/tests/simple.test.js:24
  <article><!-- react-empty: 38 --><div><section class="sc-bxivhb jwizic"><h2 class="H2__H2-dhGylN kpbCLA"><span>Start your next react project in seconds</span></h2><p><span>A highly scalable, offline-first foundation with the best DX and a focus on performance and best practices</span></p></section><section class="Section__Section-jEbZoY eivjmS"><h2 class="H2__H2-dhGylN kpbCLA"><span>Try me!</span></h2><form class="Form__Form-PASBS cEpjmP"><label for="username"><span>Show Github repositories by</span><span class="AtPrefix__AtPrefix-ivHByA dZcxpA"><span>@</span></span><input type="text" class="Input__Input-ixjKAz jCPlXI" id="username" placeholder="mxstbr" value=""></label></form><!-- react-empty: 54 --></section></div></article>