storybook-addon-specifications

Specifications Addon

Needs at least react-storybook 2.2.1

This addon for storybook will allow you to write tests based on your stories and display results directly inside storybook.

If you want to learn more about the ideas behind this addon, you can read this article : Building a react components living documentation using react-storybook..

Table of contents

• Getting Started
• Use your stories with a test runner
  • Using JEST
    • Snapshot all your stories automatically
  • Using Mocha

Getting Started

First, install the addon

npm install -D storybook-addon-specifications

Add this line to your addons.js file (create this file inside your storybook config directory if needed).

import 'storybook-addon-specifications/register';

Import the specs, describe and it functions and use it to write your tests. This example uses enzyme and expect to perform the testing.

The first parameter of the describe function must be the same as the story's name.

import { storiesOf } from '@kadira/storybook'
import { specs, describe, it } from 'storybook-addon-specifications'

import {mount} from "enzyme";
import expect from "expect";

const stories = storiesOf('Button', module);

stories.add('Hello World', function () {
  const story =
    <button onClick={action('Hello World')}>
      Hello World
    </button>;

  specs(() => describe('Hello World', function () {
    it('Should have the Hello World label', function () {
      let output = mount(story);
      expect(output.text()).toContain('Hello World');
    });
  }));

  return story;
});

Note : if you use enzyme, you will need to add the following lines to your webpack.config.js file. You also needs to add the json library to your dev dependencies.

externals: {
   'jsdom': 'window',
   'cheerio': 'window',
   'react/lib/ExecutionEnvironment': true,
   'react/lib/ReactContext': 'window',
   'react/addons': true,
 }

Use your stories with a test runner

Writing tests directly next to the component declaration used for the story is already a great thing, but it would be better if those tests can be reused with our test runner, and later be used with our CI.

To do that, the idea is to add to the test runner, all the files used for declaring stories. But because this addon redefine describe and it functions, you'll need some extra-configuration to make the tests pass within the test runner.

This repository has a directory full of examples where you can find everything that is describe here.

Using JEST

You can use the mocking functionality of jest to switch between the real describe and it implementation of jest or the one for this addon.

Inside .storybook, add a facade.js file with the following content :

import {storiesOf as storiesOfReal, action as actionReal, linkTo as linkToReal} from "@kadira/storybook"
import { specs as specsReal, describe as describeReal, it as itReal } from 'storybook-addon-specifications'

export const storiesOf = storiesOfReal;
export const action = actionReal;
export const linkTo = linkToReal;
export const specs = specsReal;
export const describe = describeReal;
export const it = itReal;

Create a __mocks__ directory within .storybook and add also a facade.js file.

export const storiesOf = function storiesOf() {
  var api = {};
  api.add = (name, func)=> {
    func();
    return api;
  };
  api.addWithInfo = (name, func)=> {
    func();
    return api;
  };
  return api;
};
export const action = () => {};

export const linkTo = () => {};

export const specs = (spec) => {
  spec();
};

export const describe = jasmine.currentEnv_.describe;
export const it = jasmine.currentEnv_.it;

Create or add to your jest config file the following line :

jest.mock('./.storybook/facade');

Inside your stories file you must now use the .storybook/facade.js file for imports.

Finally add this to your jest configuration :

"jest":{
    "setupFiles": [
      "./path/to/your/jest/config/file.js"
    ],
    "automock": false,
    }

Snapshot all your stories automatically

Warning : This part will describe how to add automatically jest snapshot to every story you write. It will allow you to take advantage of this jest feature but will not have any effect inside storybook. Indeed, you don't even need to add this addon to your project if you don't plan to use the specs() function. If I describe the idea here, it's only because it uses the trick I explain before allowing you to write tests inside stories and still be able to execute them with a test runner.

If you want to use jest snapshot testing with every story you write, that's totally possible. All you need to do is modify a bit the facade.js mock file to look like this :

import {mount} from "enzyme";

export const storiesOf = function storiesOf() {
  var api = {};
  var story;
  api.add = (name, func)=> {
    story = func();
    snapshot(name, story);
    return api;
  };
  api.addWithInfo = (name, func)=> {
    story = func();
    snapshot(name, story);
    return api;
  };
  return api;
};
export const action = () => {};

export const linkTo = () => {};

export const specs = (spec) => {
  spec();
};

export const snapshot = (name, story) => {
  describe(name + ' snapshot', function () {
    it(name, function () {
      const tree = mount(story).html();
      expect(tree).toMatchSnapshot();
    });
  });
};

export const describe = jasmine.currentEnv_.describe;
export const it = jasmine.currentEnv_.it;

For every story added to storybook, it will make a snapshot.

Here, I use enzyme to render the component under testing. I do that because it appears that if you use enzyme for others tests, it doesn't mix well with react-test-renderer. But if you do not use enzyme for your tests, then you should be good to go with react-test-renderer rendering.

If for any reason you want to choose stories that will be snapshoted, that's also possible.

1. remove snapshot() function calls from add and addWithInfo in facade.js mock file.
2. use the snapshot() function directly inside the story like you do with specs()
3. Add this line to the facade.js file used for import functions.

export const snapshot = () => {};

When storybook is going to run, it will do nothing with the snapshot function.

Using Mocha

Create the same facade.js file than for the jest configuration

Create wherever you want a new file that will mock the storybook api

export const storiesOf = function storiesOf() {
  var api = {};
  api.add = (name, func)=> {
    func();
    return api;
  };
  api.addWithInfo = (name, func)=> {
    func();
    return api;
  };
  return api;
};
export const action = () => {};

export const linkTo = () => {};

export const specs = (spec) => {
  spec();
};

export const describe = describe;
export const it = it;

Then create or add those line to a mocha config file :

import {storiesOf, action, linkTo, describe, it} from "path/to/your/mock/file";
global.storiesOf = storiesOf;
global.action = action;
global.linkTo = linkTo;
global.describe = describe;
global.it = it;

Finally add this to your mocha running script

-w test/path/to/your/config/file.js