@cucumber/cucumber

What is @cucumber/cucumber?

@cucumber/cucumber is a popular tool for Behavior-Driven Development (BDD). It allows you to write tests in a natural language that non-programmers can read, using Gherkin syntax. This makes it easier for teams to collaborate on defining the behavior of an application.

What are @cucumber/cucumber's main functionalities?

Defining Features with Gherkin

This feature allows you to define the behavior of your application in plain language using Gherkin syntax. The example defines a feature for user login with a scenario for successful login.

Feature: User login
  Scenario: Successful login
    Given the user is on the login page
    When the user enters valid credentials
    Then the user should be redirected to the dashboard

Step Definitions

Step definitions are the glue between Gherkin steps and the actual code that executes them. This example shows how to implement the steps defined in the Gherkin feature.

const { Given, When, Then } = require('@cucumber/cucumber');

Given('the user is on the login page', function () {
  // code to navigate to login page
});

When('the user enters valid credentials', function () {
  // code to enter credentials
});

Then('the user should be redirected to the dashboard', function () {
  // code to check redirection
});

Running Tests

You can run your Cucumber tests using the `cucumber-js` command. This will execute all the feature files and their corresponding step definitions.

npx cucumber-js

Other packages similar to @cucumber/cucumber

jest-cucumber

jest-cucumber is a library that allows you to use Gherkin syntax with Jest, a popular JavaScript testing framework. It provides similar functionality to @cucumber/cucumber but is integrated with Jest, making it easier to use if you are already using Jest for your unit tests.

cypress-cucumber-preprocessor

cypress-cucumber-preprocessor is a plugin for Cypress that allows you to write your Cypress tests in Gherkin syntax. It combines the power of Cypress for end-to-end testing with the readability of Cucumber.

codeceptjs

CodeceptJS is an end-to-end testing framework that supports BDD-style tests using Gherkin syntax. It provides a high-level API for writing tests and supports multiple backends like WebDriver, Puppeteer, and TestCafe.

README

Cucumber

Automated tests in plain language, for Node.js

Cucumber is a tool for running automated tests written in plain language. Because they're written in plain language, they can be read by anyone on your team. Because they can be read by anyone, you can use them to help improve communication, collaboration and trust on your team.

This is the JavaScript implementation of Cucumber. It runs on maintained versions of Node.js. You can quickly try it via CodeSandbox, or read on to get started locally in a couple of minutes.

Looking to contribute? Read our code of conduct first, then check the contributing guide to get up and running.

Install

Cucumber is available on npm:

$ npm install @cucumber/cucumber

Get Started

Let's take this example of something to test:

class Greeter {
  sayHello() {
    return 'hello'
  }
}

First, write your feature in features/greeting.feature:

Feature: Greeting

  Scenario: Say hello
    When the greeter says hello
    Then I should have heard "hello"

Next, implement your steps in features/support/steps.js:

const assert = require('assert')
const { When, Then } = require('@cucumber/cucumber')
const { Greeter } = require('../../src')

When('the greeter says hello', function () {
  this.whatIHeard = new Greeter().sayHello()
});

Then('I should have heard {string}', function (expectedResponse) {
  assert.equal(this.whatIHeard, expectedResponse)
});

Finally, run Cucumber:

$ npx cucumber-js

And see the output:

If you learn best by example, we have a repo with several example projects, that might help you get going.

Documentation

The following documentation is for main, which might contain some unreleased features. See documentation for older versions if you need it.

• Installation
• CLI
• Configuration
• Support Code
  • API Reference
  • Attachments
  • Data Tables
  • Hooks
  • Step Definitions
  • Timeouts
  • World
• Guides
  • Debugging
  • Dry run
  • ES Modules
  • Failing fast
  • Filtering which scenarios run
  • Formatters for feedback and reporting
  • Parallel running for speed
  • Profiles for composable configuration
  • Rerunning just failures
  • Retrying flaky scenarios
  • Snippets for undefined steps
  • Transpiling (from TypeScript etc)
• FAQ

Support

Support is available from the community if you need it.

Changelog

[8.7.0] - 2022-10-17

Deprecated

• Cli, PickleFilter and Runtime deprecated in favour of new API functions (see documentation) (#2136)