Mastering Browser Test Automation with Cypress and Cucumber

As an application testing expert with over 10 years of experience validating software on thousands of different browsers and devices, I often get asked – "what‘s the best way to write automated browser tests?" Based on extensive hands-on use, I firmly believe Cypress and Cucumber together provide one of the most robust and maintainable solutions for end-to-end (E2E) UI testing.

In this comprehensive guide, you‘ll learn how to maximize these tools to build fast, reliable, and reusable browser-based test suites.

Introduction to Cypress and Cucumber

Cypress is a next generation front end testing framework purpose-built for today‘s complex single-page applications. With its unique capabilities like time traveling and test auto-healing, Cypress stands out from older solutions like Selenium.

Cucumber is a popular behavior-driven development (BDD) framework that allows you to define application behavior in plain text using Gherkin syntax. This serves as living documentation of your software‘s intended functionality.

The Cypress Cucumber Preprocessor plugin effectively bridges these two tools – allowing Cypress to directly run Gherkin-defined Cucumber tests. This unlocks the readability of BDD with the resilience and speed of Cypress resulting in a very powerful combination.

Core Principles of BDD Testing

While both Cypress and Cucumber bring unique technical capabilities, it‘s important to also understand the practices and principles of BDD testing that make it so effective:

Plain Language Requirements – Using terminology and phrases familiar to business users ensures the whole team shares an understanding of intended behavior

Living Documentation – Features files serve as up-to-date documentation that evolves along with system changes

Greater Collaboration – Non-technical members can be involved in describing scenarios, freeing developers to focus on test code

Defining Behavior First – Detailing the "what" before the "how" results in software better aligned with business goals

Adopting these BDD practices enables teams to build software that matters – with automated tests verifying business value. Cypress and Cucumber support bringing these principles into your test workflows.

Installing & Configuring the Cypress Cucumber Preprocessor

Let‘s walk through setting up a new JavaScript project ready for Cypress and Cucumber test automation:

mkdir cypress-cucumber-example
cd cypress-cucumber-example  
npm init -y
npm install cypress cypress-cucumber-preprocessor --save-dev

After installing the necessary dependencies, Cypress needs to be configured to work with the Cucumber preprocessor.

Inside cypress/plugins, create an index.js file:

const cucumber = require(‘cypress-cucumber-preprocessor‘).default
module.exports = (on, config) => {
  on(‘file:preprocessor‘, cucumber()) 
}

This registers the Cucumber plugin to handle processing our feature files before test execution.

Next, configure Cypress to load the plugin and point it at the test and support file locations:

const {defineConfig} = require(‘cypress‘)

module.exports = defineConfig({
  e2e: {
    specPattern: ‘cypress/e2e/**/*.feature‘,
    supportFile: ‘cypress/support/index.js‘
  },
  "cypress-cucumber-preprocessor": {
    nonGlobalStepDefinitions: true
  }
}) 

Now everything is setup for writing Cypress tests using Cucumber!

Writing Features and Step Definitions

A sample feature file using Gherkin syntax:

Feature: Login

  Scenario: Successful login 
    Given I open the login page
    When I enter username "[email protected]" and password "123456"     
    And I click the login button
    Then I should see the user dashboard  

And step definition mappings in JavaScript:

import { Given, When, Then } from ‘cypress-cucumber-preprocessor/steps‘

Given(‘I open the login page‘, () => {
  cy.visit(‘/login‘)
})

When(‘I enter username {string} and password {string}‘, (username, password) => {
  cy.get(‘#username‘).type(username) 
  cy.get(‘#password‘).type(password)  
})

Then(‘I should see the user dashboard‘, () => {
  cy.contains(‘Welcome Back, John!‘)
    .should(‘be.visible‘)  
})

The preprocessor will match each step to the corresponding definition function to take the action.

This process allows product owners to provide examples of desired behavior using plain language. Developers can then translate them into automated tests leveraging the full power of Cypress commands and assertions.

Best Practices for Readable and Reusable Tests

Well structured test code is crucial for maintainability as an application evolves:

Feature Organization

• Group related features together in sub-folders
• Prefix naming like login_successful.feature

Step Definition Structure

• Modularize common steps into reusable definition files
• Keep definition files close to related feature files

This will help keep changes isolated and prevent unexpected breaks as code is refactored.

Tagging Tests

Strategically tagging features makes running/filtering test cases a breeze:

@smoke-tests @login  
Feature: Login

Before/After Hooks

Hooks allow setup & teardown code to be centralized:

Before(() => {
  cy.clearCookies()
  cy.exec(‘startApp‘) 
})

Following these best practices will lead to a much more maintainable automation codebase over time.

Advanced Usage and Techniques

Let‘s explore some more advanced ways to leverage Cypress and Cucumber for enhanced test capabilities:

Data Tables

Running the same steps with different values is easy using examples tables:

Scenario Outline: Login with different credentials  
  When I login as <user> with <password> 
  Then I should see the <result>

  Examples:
    | user | password | result     |
    | jdoe | 1234     | dashboard  |
    | jsmith | 12345 | error msg |

This allows iterating through multiple test data combinations improving coverage.

Test Retries

Automatically retrying failed steps helps prevent test flakiness:

When(‘I login with {string} and {string}‘, (user, password) => {
  cy.login(user, password)   
}, {
  retries: 2
})

This retry behavior decreases the likelihood of false test failures due to timing issues or server glitches.

Custom Commands

Wrapping commonly used steps into reusable custom commands is easy:

Cypress.Commands.add(‘login‘, (username, password) => { 
  cy.get(‘#username‘).type(username)
  cy.get(‘#password‘).type(password)
  cy.contains(‘Sign In‘).click()
})

Custom commands help reduce code duplication which is especially useful for more complex workflows.

There are many more ways to leverage Cypress and Cucumber – check the docs for more examples.

Executing Tests and Using the Dashboard

During test development, tests can be run via the interactive Cypress UI:

npx cypress open

This browser-based runner provides visibility into test steps with automatically generated screenshots and videos on failures.

For CI environments, headless test runs are configured like:

npx cypress run 

After setting up the Cypress Dashboard, test runs can utilize parallelization across multiple machines reducing overall execution time.

cypress run --record --key <dashboard_key> --parallel  

Test analytics and historical runs provide visibility into test effectiveness over time. Failures can be accessed and debugged right from the dashboard interface.

Maximizing Test Speed

Optimizing test performance is crucial as your test suite grows to thousands of assertions. Here are some key techniques:

Run Unit Tests First – Run fast unit tests early in the pipeline before slower UI tests to get quicker feedback.

Leverage Load Balancing – Distribute tests across multiple machines for parallel execution. This can reduce test runtimes by 70%+.

Containerize Dependencies – Provision fresh containers for each test run instead of relying on shared runtime state.

Optimize Seed Data – Only preload the minimum data required for test scenarios into test databases/APIs.

Analyze Performance – Use Cypress Audit to capture page load speed metrics.

Following performance best practices enables scale without compromising speed or stability.

Integrating with CI/CD Pipelines

Embedding automated tests into continuous delivery workflows is key for preventing regressions:

Run Tests Pre-Merge – Execute feature files against development environments before merging to main branch.

Deploy Fresh Environments – Utilize containers to spin up isolated and consistent test environments.

Automate Data Setups – Seed databases and APIs with test data programmatically.

Set Exit Criteria – Fail builds if test pass % drops below a configured threshold.

Archive Artifacts – Save videos, screenshots and test metadata through the pipeline for troubleshooting.

These tips will help provide confidence at each stage that quality criteria is met.

Conclusion

I hope this guide has shown how Cypress and Cucumber can form a powerful combination for reliable test automation. By leveraging the capabilities outlined here, teams can benefit from faster feedback, greater collaboration between roles, and more maintainable tests over time. The practices described will help you maximize productivity on the journey towards continuous testing. Reach out via my site with any other questions!