How to test react-native components which are using react-i18next? - react-native

Question

I'm trying to use jest to start testing an established RN app. The majority of the components are wrapped in withNamespaces provided by react-i18next.
When i run tests i have this error:
FAIL tests/setting.test.js
● Test suite failed to run
TypeError: Cannot read property 'type' of undefined
4 |
5 | i18n
> 6 | .use(initReactI18next)
| ^
7 | .init({
8 | fallbackLng: 'en',
9 | resources: {
at I18n.use (node_modules/i18next/dist/commonjs/i18next.js:260:16)
at Object.<anonymous> (config/i18nForTest.js:6:1)
at Object.<anonymous> (tests/setting.test.js:5:43)
I followed the doc example and what i've done basically is :
made i18n config for tests :
import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';
i18n
.use(initReactI18next)
.init({
fallbackLng: 'en',
resources: {
en: {},
fr: {}
},
// have a common namespace used around the full app
ns: ['translations'],
defaultNS: 'translations',
debug: true,
interpolation: {
escapeValue: false, // not needed for react!!
},
});
export default i18n;
then wrote some tests:
import 'react-native';
import React from 'react';
import renderer from 'react-test-renderer';
import {I18nextProvider} from 'react-i18next';
import i18n from 'config/i18nForTest';
import Settings from 'containers/Settings';
it('Does Settings renders correctly?', () => {
const tree = renderer
.create(
<I18nextProvider i18n={i18n}>
<Settings t= {key => key} />
</I18nextProvider>,
)
.toJSON();
expect(tree).toMatchSnapshot();
});
you can find here my jest config in package.json:
"jest": {
"setupFiles": ["<rootDir>/jest.setup.js"],
"preset": "react-native",
"testMatch": [
"<rootDir>/tests/**/*.test.js?(x)",
"<rootDir>/src/**/*.test.js"
],
"transformIgnorePatterns": ["node_modules/(?!(#react-native-community|react-navigation|react-native))"
],
"transform": {
"^.+\\.(js)$": "<rootDir>/node_modules/react-native/jest/preprocessor.js"
}
},
THANKS!

Answer 1

I finally found a solution for my problem.
I think the testing example provided in the doc is for v10 and i'm using v9.
So i have modified the i18n config test to use reactI18nextModule so its like this now:
import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';
import { reactI18nextModule } from 'react-i18next';
i18n
.use(reactI18nextModule)
.init({
fallbackLng: 'en',
resources: {
en: {},
fr: {}
},
// have a common namespace used around the full app
ns: ['translations'],
defaultNS: 'translations',
debug: true,
interpolation: {
escapeValue: false, // not needed for react!!
},
});
export default i18n;
after that now i can omit i18nProvider in the testing components like this:
import 'react-native';
import React from 'react';
import renderer from 'react-test-renderer';
import {I18nextProvider} from 'react-i18next';
import i18n from 'config/i18nForTest';
import {Settings} from 'containers/Settings'; // to get redux connected component import Setting without {}
it('Does Settings renders correctly?', () => {
const tree = renderer
.create(
<Settings t={key => key} />
)
.toJSON();
expect(tree).toMatchSnapshot();
});