Jest tests can't process import statement

[ijdickinson]

Version

3.0.0-rc.2

Reproduction link

https://github.com/ijdickinson/vue-cli-jest-problem

Steps to reproduce

This is a similar problem to 1475, but I can't find a way to resolve it. I created a new app with vue-cli, selecting Jest tests. I added a simple POJO (src/models/model.js) and a test for it (tests/model.spec.js).

To repro the problem, just npm run test:unit

What is expected?

Tests to pass, or at least run

What is actually happening?

$ npm run test:unit

> test-application@0.1.0 test:unit /home/ian/workspace/project/test-application
> vue-cli-service test:unit

 FAIL  tests/unit/model.spec.js
  ● Test suite failed to run

    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://facebook.github.io/jest/docs/en/configuration.html

    Details:

    /home/ian/workspace/project/test-application/tests/unit/model.spec.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import "core-js/modules/es6.promise";
                                                                                             ^^^^^^

    SyntaxError: Unexpected token import

      at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:402:17)

 PASS  tests/unit/HelloWorld.spec.js

Test Suites: 1 failed, 1 passed, 2 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        1.427s
Ran all test suites.
 ERROR  jest exited with code 1.

[minorgod]

I was able to fix this issue by adding the following to the jest.config.js transform section:

'^.+\\.js$': 'babel-jest',

[ijdickinson]

@minorgod Thanks, I confirm that this does indeed fix my problem.

So, should it be added to the standard template for jest.config.js? Or is it something that just needs to be mentioned in the docs?

[Akryum]

This looks like a bug, since it's done here.

[marlonbarcarol]

Adding '^.+\\.js$': 'babel-jest' does fixes it, I was facing the same problem with vue-cli: 3.0.0-rc.3.
Just a reminder that it should be placed in the end of the transform object, right after '^.+\\.tsx?$': 'ts-jest', otherwise it won't work.

Update: I've started to get the same thing again, so I had to run node node_modules/.bin/jest --clearCache to solve it.

[onigunn]

Adding '^.+\\.js$': 'babel-jest' was not enough for me. Tests run only on empty cache once and started throwing Unexpected token errors on change. As mentioned here I also had to add transformIgnorePatterns ['<rootDir>/node_modules/'] to my jest.config.js

Full jest.config.js

module.exports = {
  moduleFileExtensions: ['js', 'jsx', 'json', 'vue'],
  transform: {
    '^.+\\.vue$': 'vue-jest',
    '.+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$':
      'jest-transform-stub',
    '^.+\\.(js|jsx)?$': 'babel-jest'
  },
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1'
  },
  snapshotSerializers: ['jest-serializer-vue'],
  testMatch: [
    '<rootDir>/(tests/unit/**/*.spec.(js|jsx|ts|tsx)|**/__tests__/*.(js|jsx|ts|tsx))'
  ],
  transformIgnorePatterns: ['<rootDir>/node_modules/']
};

For now everything seems to be good.

[tinchox5]

Same issue. None of the proposed solutions works for me

[hajarrashidi]

+1

[beey-keey]

Same issue about my tests.. Again none of the solutions worked for me..

[rahulakurati]

+1

[marcusnunes]

Is everyone here using windows? I didn't reproduce the error on mac.

[Akryum]

Note: I can't reproduce on the dev environment.