Testing React-Intl components with Enzyme's mount() and shallow() methods. This is a helper function which wraps the `intl` context around your component tests in an easy and efficient way.

README.md

When using Enzyme and React-Intl you are likely run into the issues when testing components that use some of React-Intl's components or injected formatting functions. These helper functions (mountWithIntl and shallowWithIntl) aim to address some of the below errors:

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

TypeError: Cannot read property 'getInstance' of null

Error: ReactWrapper::state() can only be called on the root

Checkout this question at StackOverflow for a complete overview of the issues I ran into:

Injecting react-intl object into mounted Enzyme components for testing

CustomComponent-test.js

import { mountWithIntl } from 'helpers/intl-enzyme-test-helper.js';

const wrapper = mountWithIntl(
  <CustomComponent />
);

expect(wrapper.state('foo')).to.equal('bar');    // OK
expect(wrapper.text()).to.equal('Hello World!'); // OK

CustomComponent.js

import React from 'react';
import { FormattedMessage } from 'react-intl';

class CustomComponent extends React.Component {
  state = {
    foo: 'bar'
  }

  render() {
    return (
      <div>
        <FormattedMessage id="world.hello" defaultMessage="Hello World!" />
      </div>
    );
  }
}

intl-enzyme-test-helper.js

/**
 * Components using the react-intl module require access to the intl context.
 * This is not available when mounting single components in Enzyme.
 * These helper functions aim to address that and wrap a valid,
 * English-locale intl context around them.
 */

import React from 'react';
import { IntlProvider, intlShape } from 'react-intl';
import { mount, shallow } from 'enzyme';

// You can pass your messages to the IntlProvider. Optional: remove if unneeded.
const messages = require('../locales/en'); // en.json

// Create the IntlProvider to retrieve context for wrapping around.
const intlProvider = new IntlProvider({ locale: 'en', messages }, {});
const { intl } = intlProvider.getChildContext();

/**
 * When using React-Intl `injectIntl` on components, props.intl is required.
 */
function nodeWithIntlProp(node) {
  return React.cloneElement(node, { intl });
}

/**
 * Export these methods.
 */
export function shallowWithIntl(node) {
  return shallow(nodeWithIntlProp(node), { context: { intl } });
}

export function mountWithIntl(node) {
  return mount(nodeWithIntlProp(node), {
    context: { intl },
    childContextTypes: { intl: intlShape }
  });
}