Error

 Jest encountered an unexpected token

    This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.

    By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".

    Here's what you can do:
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/en/configuration.html

    Details:

    /Users/yjlu@thoughtworks.com/Code/Git/Porsche/cool-frontend/node_modules/antd/es/notification/style/css.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import '../../style/index.css';
                                                                                             ^^^^^^

Test environment

"antd": "^3.11.2",
"@babel/core": "7.1.0",
"babel-jest": "^23.6.0",
"jest": "^23.6.0",

// .babelrc
{
  "presets": ["@babel/react","@babel/env"],
  "plugins": [
    "transform-class-properties",
    ["import", { "libraryName": "antd", "libraryDirectory": "es", "style": "css" }]
  ]
}

Root cause

babel-jest does not transpile import/export in node_modules when Babel 7 is used #6229

Solution

1. rename .babelrc to babel.config.js which will export .babelrc object.
2. Adding transformIgnorePatterns to my Jest config in package.json:

"transformIgnorePatterns": [
      "/node_modules/antd/es/notification/style/index.js"
],

3. create a mock style js file <rootDir>/__mocks__/styleMock.js

// styleMock.js
module.exports = {};

And use it in moduleNameMapper:

"moduleNameMapper": {
      "\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
      "\\.(css)$": "<rootDir>/__mocks__/styleMock.js"
    }

After I did these 3 steps, I found that it takes a long time to run my test cases. And after I add node_modules in moduleDirectories in jest config, it runs smoothly.

// jest.config.json
"moduleDirectories": ["....", "node_modules"]