Trying to unit test a React component using Jest and Enzyme

Question

I am trying to run a simple jest and enzyme test against a react component and test throws: ReferenceError: React is not defined. I followed all simple tutorials on jest and react testing but all of them resulted in the same exception. I used npm test and result was the same as yarn test, React not defined. I am confused. Any help would be appreciated.

Checkbox.test.jsx: simple test

import { shallow } from 'enzyme';
import sinon from 'sinon';

import Checkbox from './Checkbox';

describe('<Checkbox />', () => {
  it('should render three <Checkbox /> components', () => {
    const wrapper = shallow(<Checkbox />);
    expect(wrapper.prop('title')).toEqual('Events — Event Radar');
  });
});

Console log

$ yarn test
FAIL src\components\ReusableComponents\Checkbox.test.jsx (5.248s)
  <Checkbox />
    × should render three <Checkbox /> components (4ms)

  ● <Checkbox /> › should render three <Checkbox /> components

    ReferenceError: React is not defined

      at Object.<anonymous> (src/components/ReusableComponents/Checkbox.test.jsx:8:40)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        10.517s
Ran all test suites.
error Command failed with exit code 1.

package.json

{
  "name": "mi-benchmarking-frontend",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "axios": "^0.17.0",
    "classnames": "^2.2.5",
    "history": "^4.7.2",
    "prop-types": "^15.6.0",
    "react": "^16.0.0",
    "react-bootstrap": "^0.31.5",
    "react-bootstrap-table": "^4.1.1",
    "react-dom": "^16.0.0",
    "react-logger": "^1.1.0",
    "react-pagination-table": "^1.1.0",
    "react-redux": "^5.0.6",
    "react-router": "^3.2.0",
    "react-router-redux": "^4.0.8",
    "react-scripts": "1.0.14",
    "react-simple-paginate": "^1.1.0",
    "react-table": "^6.6.0",
    "redux": "^3.7.2",
    "redux-logger": "^3.0.6",
    "redux-thunk": "^2.2.0"
  },
  "devDependencies": {
    "autoprefixer": "^6.3.6",
    "babel-core": "^6.26.0",
    "babel-eslint": "^6.0.4",
    "babel-jest": "^21.2.0",
    "babel-loader": "^6.2.4",
    "babel-plugin-react-require": "^3.0.0",
    "babel-plugin-syntax-object-rest-spread": "^6.13.0",
    "babel-plugin-transform-object-spread-inline": "0.0.2",
    "babel-polyfill": "^6.8.0",
    "babel-preset-es2015": "^6.6.0",
    "babel-preset-react": "^6.5.0",
    "babel-preset-stage-0": "^6.5.0",
    "clean-webpack-plugin": "^0.1.13",
    "copy-webpack-plugin": "^4.0.0",
    "css-loader": "^0.23.1",
    "enzyme": "^3.1.0",
    "enzyme-adapter-react-16": "^1.0.2",
    "eslint": "^3.19.0",
    "eslint-loader": "^1.5.0",
    "eslint-plugin-babel": "^4.1.2",
    "eslint-plugin-react": "^7.1.0",
    "extract-text-webpack-plugin": "^3.0.2",
    "file-loader": "^1.1.5",
    "html-webpack-plugin": "^2.16.1",
    "jest": "^21.2.1",
    "jest-enzyme": "^4.0.1",
    "json-loader": "^0.5.4",
    "postcss-loader": "^0.9.1",
    "redux-devtools": "^3.4.0",
    "sinon": "^4.0.2",
    "style-loader": "^0.13.1",
    "url-loader": "^0.5.7",
    "webpack": "2.6.1",
    "webpack-dev-server": "2.5.0",
    "webpack-manifest-plugin": "1.1.0"
  },
  "scripts": {
    "start": "npm run build:dev",
    "build:dev": "webpack-dev-server --inline --history-api-fallback",
    "build:test": "webpack --define process.env.NODE_ENV='test'",
    "build:stage": "webpack --define process.env.NODE_ENV='stage'",
    "build:prod": "webpack --define process.env.NODE_ENV='production'",
    "eject": "react-scripts eject",
    "test": "jest",
    "test:watch": "jest --watch",
    "test:coverage": "jest --coverage"
  },
  "jest": {
    "setupTestFrameworkScriptFile": "./node_modules/jest-enzyme/lib/index.js"
  }
}

Answer 1

Import React in your test and the error should disappear:

import React from 'react';

I tried removing this import in one of my tests and I got the same error you mentioned.

I hope this helps.