Jest Cucumber Fusion

Write 'pure' cucumber test in Jest without syntax clutter

Overview

Build on top of Jest-cucumber, Jest-Cucumber-Fusion handle the writing of the corresponding Jest test steps using an uncluttered cucumber style. Instead of using describe and it blocks, you instead write a Jest test for each scenario, and then define Given, When, and Then step definitions inside of your Jest tests. Jest-Cucumber-Fusion then allows you to link these Cucumber tests to your javascript Cucumber feature steps. Adding a Fusioncall, the links between your Feature definition and your Steps definition is handled automatically and the necessary scaffolding for jest-cucumber is build behind the scene. Now use jest naturally in your project like you would use the native Cucumber library.

Motivation

Jest-cucumber is an amazing project but forces you to write a lot of repetitive scaffolding code to setup the link betwen Jest and Cucumber. With Jest-Cucumber-Fusion, it really takes only the minimal code possible:

• a Cucumber Feature file with gherkin sentences
• a Cucumber Step definition file with your javascript validation code, ended with the Fusion function to link the two

Getting Started

Install Jest Cucumber Fusion:

npm install jest-cucumber-fusion --save-dev

Add a Feature file:

###filename: rocket-launching.feature
Feature: Rocket Launching

Scenario: Launching a SpaceX rocket
  Given I am Elon Musk attempting to launch a rocket into space
  When I launch the rocket
  Then the rocket should end up in space
  And the booster(s) should land back on the launch pad
  And nobody should doubt me ever again

Add the following to your package.json configuration:

"jest": { "testMatch": [ "**/*.steps.js" ] }

Add a your Cucumber Step definition file and load Fusion

//filename: rocket-launching.steps.js
const { Given, When, Then, And, But, Fusion } = require( 'jest-cucumber-fusion' )

Load any dependency you need to do your test

//filename: rocket-launching.steps.js
const { Given, When, Then, And, But, Fusion } = require( 'jest-cucumber-fusion' )

const { Rocket } = require( '../../src/rocket' )
let rocket

Add steps definitions:

//filename: rocket-launching.steps.js
const { Given, When, Then, And, But, Fusion } = require( 'jest-cucumber-fusion' )

const { Rocket } = require( '../../src/rocket' )
let rocket

Given( 'I am Elon Musk attempting to launch a rocket into space', () => {
    rocket = new Rocket()
} )

When( 'I launch the rocket', () => {
    rocket.launch()
} )

Then( 'the rocket should end up in space', () => {
    expect(rocket.isInSpace).toBe(true)
} )

And( /^the booster\(s\) should land back on the launch pad$/, () => {
    expect(rocket.boostersLanded).toBe(true)
} )

But( 'nobody should doubt me ever again', () => {
    expect('people').not.toBe('haters')
} )

Adding the Fusion() call at the end of the Step definition file

You have to match it with your Cucumber Feature definition file:

//filename: rocket-launching.steps.js
const { Given, When, Then, And, But, Fusion } = require( 'jest-cucumber-fusion' )

const { Rocket } = require( '../../src/rocket' )
let rocket

Given( 'I am Elon Musk attempting to launch a rocket into space', () => {
    rocket = new Rocket()
} )

When( 'I launch the rocket', () => {
    rocket.launch()
} )

Then( 'the rocket should end up in space', () => {
    expect(rocket.isInSpace).toBe(true)
} )

And( /^the booster\(s\) should land back on the launch pad$/, () => {
    expect(rocket.boostersLanded).toBe(true)
} )

But( 'nobody should doubt me ever again', () => {
    expect('people').not.toBe('haters')
} )


Fusion( 'rocket-launching.feature' )

Adding coverage

Since we're using jest, it is very easy to generate the code coverage of your Cucumber test:

"jest": {
    "testMatch": [
      "**/*.steps.js"
    ],
    "coveragePathIgnorePatterns": [
      "/node_modules/",
      "/test/"
    ],
    "coverageDirectory": "./coverage/",
    "collectCoverage": true
  }

Additional Documentation

• Gherkin tables
• Step definition arguments
• Scenario outlines
• Re-using step definitions
• Configuration options
• Running the examples
• Language