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.
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:
First, write your main code in src/index.js
:
class Greeter {
sayHello() {
return 'hello'
}
}
module.exports = {
Greeter
}
Then, 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.
Support
Support is available from the community if you need it.