nodejs_example.md

Setup

• Install Node.js (6 or higher)

• Install Cucumber modules with yarn or npm

  yarn add -D cucumber@latest
  
  npm i -D cucumber@latest
  

• Add the following files

  # features/simple_math.feature
  Feature: Simple maths
    In order to do maths
    As a developer
    I want to increment variables
  
    Scenario: easy maths
      Given a variable set to 1
      When I increment the variable by 1
      Then the variable should contain 2
  
    Scenario Outline: much more complex stuff
      Given a variable set to <var>
      When I increment the variable by <increment>
      Then the variable should contain <result>
  
      Examples:
        | var | increment | result |
        | 100 |         5 |    105 |
        |  99 |      1234 |   1333 |
        |  12 |         5 |     17 |

  // features/support/world.js
  const { setWorldConstructor } = require("cucumber");
  
  class CustomWorld {
    constructor() {
      this.variable = 0;
    }
  
    setTo(number) {
      this.variable = number;
    }
  
    incrementBy(number) {
      this.variable += number;
    }
  }
  
  setWorldConstructor(CustomWorld);

  // features/support/steps.js
  const { Given, When, Then } = require("cucumber");
  const assert = require("assert").strict
  
  Given("a variable set to {int}", function(number) {
    this.setTo(number);
  });
  
  When("I increment the variable by {int}", function(number) {
    this.incrementBy(number);
  });
  
  Then("the variable should contain {int}", function(number) {
    assert.equal(this.variable, number);
  });

• Run ./node_modules/.bin/cucumber-js