jest

Storybook addon Jest

Brings Jest results in storybook.

Framework Support

Checkout the above Live Storybook.

Getting started

Install

npm install --save-dev @storybook/addon-jest

or

yarn add --dev @storybook/addon-jest

Jest Configuration

When running Jest, be sure to save the results in a json file:

package.json

"scripts": {
  "test:generate-output": "jest --json --outputFile=jest-test-results.json"
}

You may want to add it the result file to .gitignore, since it's a generated file:

jest-test-results.json

But much like lockfiles and snapshots checking-in generated files can have certain advantages as well. It's up to you. We recommend to do check in the test results file so starting storybook from an clean git clone doesn't require running all tests first, but this can mean you'll experience merge conflicts on this file in the future. (re-generating this file is super easy though, just like lockfiles and snapshots)

Generating the test results

You need to make sure the generated test-restuls file exists before you start storybook. During development you will likely start jest in watch-mode and so the json file will be re-generated every time code or tests change.

npm run test:generate-output -- --watch

This change will then be HMR (hot module reloaded) using webpack and displayed by this addon.

If you want to pre-run jest automaticly during development or a static build, you may need to consider that if your tests fail, the script receives a non-0 exit code and will exit. You could create a prebuild:storybook npm script, which will never fail by appending || true:

"scripts": {
  "test:generate-output": "jest --json --outputFile=.jest-test-results.json || true",
  "test": "jest",
  "prebuild:storybook": "npm run test:generate-output",
  "build:storybook": "build-storybook -c .storybook -o build/",
  "predeploy": "npm run build:storybook",
  "deploy": "gh-pages -d build/",
}

Register

Register addon at .storybook/addons.js

import '@storybook/addon-jest/register';

Usage

Assuming that you have created a test files MyComponent.test.js and MyOtherComponent.test.js

In your story.js

import results from '../.jest-test-results.json';
import { withTests } from '@storybook/addon-jest';

storiesOf('MyComponent', module)
  .addDecorator(withTests({ results })('MyComponent', 'MyOtherComponent'))
  .add('This story shows test results from MyComponent.test.js and MyOtherComponent.test.js', () => (
    <div>Jest results in storybook</div>
  ));

Or in order to avoid importing .jest-test-results.json in each story, you can create a simple file withTests.js:

import results from '../.jest-test-results.json';
import { withTests } from '@storybook/addon-jest';

export default withTests({
  results,
});

Then in your story:

// import your file
import withTests from '.withTests';

storiesOf('MyComponent', module)
  .addDecorator(withTests('MyComponent', 'MyOtherComponent'))
  .add('This story shows test results from MyComponent.test.js and MyOtherComponent.test.js', () => (
    <div>Jest results in storybook</div>
  ));

withTests(options)

• options.results: OBJECT jest output results. mandatory
• filteExt: STRING test file extention. optionnal. This allow you to write "MyComponent" and not "MyComponent.test.js". It will be used as regex to find your file results. Default value is ((\\.specs?)|(\\.tests?))?(\\.js)?$. That mean it will match: MyComponent.js, MyComponent.test.js, MyComponent.tests.js, MyComponent.spec.js, MyComponent.specs.js...

TODO

• Add coverage
• Display nested test better (describe)
• Display the date of the test
• Add unit tests
• Add linting
• Split

Contributing

Every ideas and contributions are welcomed.

Licence

MIT © 2017-present Renaud Tertrais