Cannot find module 'ReactNative' from 'react-native.js' w/ Jest

Question

I'm attempting to use jest (v20.0.0) w/ my React Native application (v0.42.0) however when I run yarn jest I get the following error:

yarn jest v0.27.5
$ jest
 FAIL  __tests__/routing/router-test.js
  ● Test suite failed to run

    Cannot find module 'ReactNative' from 'react-native.js'

      at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:179:17)
      at Object.<anonymous> (node_modules/react-native/Libraries/react-native/react-native.js:188:25)

Here is the jest portion of my package.json

  "jest": {
    "testPathIgnorePatterns": [
      "/node_modules/"
    ],
    "transformIgnorePatterns": [
      "node_modules/(?!react-native|react-native-geocoding)/"
    ],
    "globals": {
      "__DEV__": false
    },
    "collectCoverage": false
  },

Update #1

Here's the failing test file (I stripped out everything except the import and the error persists).

import 'react-native';
import React from 'react';

describe('Router', () => {

});

@JasonGaare I've posted it but it's just an import of `react-native`. — Kyle Decot, Sep 11 '17 at 21:10
Your test file is incomplete. `import 'react-native'` from what? And also, wouldnt it be `import { stuff } from 'react-native'` — Max Baldwin, Sep 11 '17 at 21:19
@MaxBaldwin that's a valid import form. It's purpose is to import a module which has side effects for those side effects alone. There is no `from` clause used in that case. — Aluan Haddad, Sep 11 '17 at 22:16
@AluanHaddad in javascript and React that is not true. Unless you have some docs that say otherwise. Jest is a javascript testing framework for React, so importing like that isn't going to work. — Max Baldwin, Sep 12 '17 at 14:38
It most certainly works that way @MaxBaldwin. See [here](https://github.com/facebook/react-native/blob/1e8f3b11027fe0a7514b4fc97d0798d3c64bc895/local-cli/templates/HelloWorld/__tests__/App.js#L1) for an example in react native's repo. — Kyle Decot, Sep 12 '17 at 15:59
@KyleDecot I guess you are right. You learn something new everyday — Max Baldwin, Sep 13 '17 at 21:09
Do you also `import React from 'react'` in your test? See breaking changes after v0.26: https://github.com/facebook/react-native/releases/tag/v0.26.0. — Tom Davies, Sep 14 '17 at 15:05
@TomDavies I have tried adding this but since this line comes after the import of react native (same in example from Facebook that I previously linked to) it makes no difference. — Kyle Decot, Sep 18 '17 at 11:30
Not sure if this is the issue, but there should be a `preset: "react-native"` part in your jest config, like stated here https://facebook.github.io/jest/docs/en/tutorial-react-native.html — LYu, Sep 20 '17 at 23:40
Have you tried to import `react` before `react-native`? The link to your issue is not obvious, but it may be worth clearing this out. — RaphaMex, Dec 20 '17 at 03:06

score 2 · Answer 1 · answered Feb 16 '18 at 20:50

2

Your Jest configuration is missing React Native preset:

"jest": {
  "preset": "react-native"
}

It's available by default in this form since react-native@0.38.0.

answered Feb 16 '18 at 20:50

Michał Pierzchała

1,762
1
15
20

score 0 · Answer 2 · answered Dec 20 '17 at 15:20

Here is a config that works for me.

  "devDependencies": {
    "babel-jest": "21.0.2",
    "babel-plugin-module-resolver": "2.7.1",
    "babel-preset-es2015": "6.24.1",
    "babel-preset-react-native": "1.9.1",
    "jest": "21.0.2"
  },
  "jest": {
    "preset": "react-native",
    "automock": false,
    "testMatch": [
      "<rootDir>/source/**/__tests__/*.js"
    ],
    "moduleFileExtensions": [
      "js",
      "jsx"
    ],
    "moduleDirectories": [
      "node_modules",
      "<rootDir>/source"
    ],
    "globals": {
      "__DEV__": true
    }
  },

Cannot find module 'ReactNative' from 'react-native.js' w/ Jest

Update #1

2 Answers2