Automating Testing with Cucumber and Selenium: A 2500+ Word Expert Guide

Have you ever felt frustrated with the quality of your web application after it was deployed, despite extensive testing during development? As a testing expert with over 10 years of experience across 3500+ real devices and browsers, I have been in your shoes. The solution? Comprehensive test automation using Cucumber and Selenium.

In this detailed 2500+ word guide, I will explain everything you need to know to start automating browser testing with these amazing open-source tools. We‘ll cover:

• Key concepts about Cucumber and Selenium
• Step-by-step guide to set up test automation
• Writing and running automated test scripts
• Best practices for test design, organization and reporting
• Tips to scale automation testing and integrate with CI/CD workflows

I will share plenty of examples from real-world test automation initiatives I have led over the years. My goal is to help you gain the confidence to automate testing for your web apps the right way and take your projects to the next level. Shall we get started?

Introduction to Selenium and Cucumber

Before we jump into setting up automation, let me briefly explain what Selenium and Cucumber are exactly.

What is Selenium?

Selenium is an open-source test automation tool that allows you to replicate user actions in the browser to test your web applications. The Selenium WebDriver API lets you perform actions like:

• Launching browsers (Chrome, Firefox etc.)
• Navigating to web pages and filling out forms
• Clicking buttons and links on the page
• Executing JavaScript

And much more! It supports multiple languages like Java, C#, Python etc.

Here is a simple Selenium test script example in Java:

// Initialize driver 
WebDriver driver = new ChromeDriver();

// Open webapp login page
driver.get("http://webapp.com/login");  

// Find username field and pass input
driver.findElement(By.id("user")).sendKeys("John");

// Click Submit button
driver.findElement(By.cssSelector("#submitBtn")).click();

This allows you to automate and test real user flows on your web application!

What is Cucumber?

Cucumber is a testing framework that implements Behavior Driven Development (BDD) – where you first start by defining application behavior and writing test cases around it.

In Cucumber, you describe desired behavior of the app in simple English-like language called Gherkin. Here is how it looks:

Feature: Login Action
   Scenario: Check valid login
      Given I am on the login page
      When I submit valid credentials  
      Then I should see homepage

This gives non-technical people a way to define test scenarios, while developers can map those scenarios to automated Selenium test scripts. This bridges the communication gap between business and technical teams.

Now let‘s look at how Selenium and Cucumber work hand-in-hand to enable automated browser testing.

Automating Browser Testing with Cucumber + Selenium

Cucumber allows you to create a test automation framework by defining app behavior specifications and scenarios. Selenium then becomes the execution engine that drives actions and assertions on the browser.

Key Benefits You Get:

✔️ Simple way to document requirements and expected outcomes
✔️ Tests written in human readable language
✔️ Promotes collaboration between teams
✔️ Reusable test building blocks
✔️ Automated end-to-end testing

Cucumber‘s integration with Selenium WebDriver lets you automate testing web apps across different browsers like Chrome, Firefox, Safari etc. You can replicates all kinds of user flows – happy paths, negative scenarios, edge cases and more.

Let‘s now look at the key components that make up the Cucumber+Selenium test automation framework.

Understanding the Cucumber Test Automation Framework

There are primarily 5 components that enable automation with Cucumber:

1. Feature Files

Feature files contain test scenarios written using the Gherkin language in Given/When/Then format. They specify app behavior and outcomes.

Example

Feature: Login Action
   Scenario: Valid Credentials
     Given user is on login page
     When user submits valid credentials
     Then user is redirected to homepage

Feature files serve as your high level test plans.

2. Step Definitions

Step definitions contain actual test automation code and steps mapped to each Gherkin step. You write Selenium WebDriver code here to interact with browser.

Example

@Given("user is on login page")
public void navigateToLoginPage() {
  // Selenium code to launch browser 
  // and open login page
}

@When("user submits valid credentials")
public void submitValidCreds() {
  // Find username, password fields
  // Input credentials 
  // Click submit
}  

Step definitions is where you automate interaction with elements on web pages to execute a test scenario.

3. Page Objects

Page objects allow you to model page UI and create reusable selectors and methods to interact with page elements. This makes tests more readable and maintainable.

Here is an example LoginPage page object:

public class LoginPage {

  WebElement username;
  WebElement password; 
  WebElement submitBtn;

  // Initialize element selectors 

  public void login(String usr, String pwd) { 
    username.sendKeys(usr);
    password.sendKeys(pwd);
    submitBtn.click();  
  }
}

And used in a step definition as:

LoginPage login = new LoginPage();
login.login("testuser", "Test@123");

4. Hooks

Hooks allow you to execute setup and teardown code before and after each test scenario like launching driver, exiting browser etc.

Example

@Before 
public void setup() {
  // Initialize chrome driver 
}

@After
public void close() {
  // Close browser
}

5. Runner Class

The runner class allows Cucumber to run feature files using JUnit. You specify location of step definitions and other configs here.

@RunWith(Cucumber.class)
@CucumberOptions(
  features = "src/test/resources"
  glue = "stepdefinitions"
)
public class TestRunner {
}

That covers the key components that make up the Cucumber test automation framework architecture integrated with Selenium!

Now let‘s look at how to setup this framework.

Step-by-Step Guide to Setup Selenium Cucumber Framework

Let me walk you through the end-to-end steps I follow to setup Selenium Cucumber test automation framework:

Step 1: Install Prerequisites

You need Java, an IDE (Eclipse/IntelliJ), Maven and browser drivers installed.

Step 2: Create Maven Project

Create a new Maven project in your IDE for building framework.

Step 3: Add Dependencies

Open pom.xml file and add the following key dependencies:

<!-- https://mvnrepository.com/artifact/io.cucumber/cucumber-java -->
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-java</artifactId>
    <version>7.3.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/io.cucumber/cucumber-junit -->
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-junit</artifactId>
    <version>7.3.3</version>
    <scope>test</scope>
</dependency>   

<!-- https://mvnrepository.com/artifact/org.seleniumhq.selenium/selenium-java -->
<dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>4.7.2</version>
</dependency>

This will install Cucumber, Selenium and JUnit packages needed for test automation.

Step 4: Create Feature Files

Next, create the *.feature files inside src/test/resources/features folder. This is where you write test scenarios in Gherkin language.

For example:

# file: login.feature 

Feature: Login Feature
  Scenario: Login with valid credentials
    Given user navigates to login form
    When user enters username and password
    Then user is redirected to home page

Feature files contain your test plans and expected outcomes.

Step 5: Create Step Definitions

Under src/test/java folder create Java class files with @Given, @When methods mapped to each step. Here is where test execution happens.

For example:

import io.cucumber.java.en.*;

public class LoginSteps {

  @Given("user navigates to login form")
  public void loadLoginForm() {
    // Selenium code to launch browser
    // and open login page 
  }

  @When("user enters username and password")
  public void enterCredentials() {
     // Find username, password elements
     // Enter valid data
  }

}

Map feature file steps to Java+Selenium code to automate!

Step 6: Configure Runner Class

Create a JUnit runner class to configure and trigger test execution.

@RunWith(Cucumber.class)
@CucumberOptions(
  features = "src/test/resources/features",
  glue = "stepdefinitions"
)
public class TestRunner {

}

Now your Selenium Cucumber framework is ready for test automation!

Writing Effective Automated Test Scenarios

Let‘s take a sample scenario and automate browser testing end-to-end. We will automate a web application login flow with valid and invalid data test cases.

Feature File

Feature: Webapp Login Feature
  Scenario: Login with valid credentials
    Given user opens login page
    When user submits valid username and password 
    Then user is redirected to homepage

  Scenario: Login with invalid credentials  
    Given user opens login page 
    When user submits invalid username and password
    Then error message is displayed

Step Definition

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;

public class LoginSteps {

  WebDriver driver; 

  @Given("user opens login page")
  public void navigateToLogin() {
    driver = new ChromeDriver();
    driver.get("http://webapp/login");
  }  

  @When("user submits valid username and password")
  public void submitValidCreds() {
    driver.findElement(By.id("user")).sendKeys("johndoe"); 
    driver.findElement(By.id("pass")).sendKeys("J0hn@123");
    driver.findElement(By.id("loginBtn")).click();
  }

  @Then("user is redirected to homepage") 
  public void verifyLogin() {
    Assert.assertTrue(driver.getCurrentUrl().contains("home"));
  }  

  // Similarly other step methods 
}

Execute these automated scripts on multiple environments and browsers during the development cycle to catch issues early.

Best Practices for Effective Test Automation

Let me share top best practices I always follow when automating testing using Cucumber Selenium:

1. Start Small, Expand Test Coverage

Start by automating 1-2 critical user journeys first. Once scripts are stable, keep expanding test coverage.

2. Reuse Page Objects

Create modular page objects for improved code reusability and easier maintenance.

3. Parameterize Input Data

Externalize test data from scripts for easier test data management using example tables:

Examples: 
|username|password|  
|user1|pwd1|
|user2|pwd2|

4. Implement CI/CD Early

Configure a CI/CD pipeline to trigger test suite automatically. Use tools like Jenkins.

5. Run Tests Across Environments

Run automated tests across multiple environments – dev, test, staging etc. to identify issues quickly.

Some Other Best Practices Include:

• Maintaining feature files as central test plans
• Using hooks effectively for repeated setup/teardown tasks
• Adding custom reporting, screenshots and logs for test failures
• Tagging tests to group them logically
• Tracking test coverage and completion metrics

These best practices allow you to setup a robust test automation process and framework for continuous testing.

Advanced Tips and Tricks

Let me also share some advanced tips I have learned for smooth test automation:

1. Decompose Tests via Composable Modules

Break down tests into small reusable steps and methods to avoid duplication. Creates composable building blocks.

2. Implement Smart Wait Strategies

Use explicit and fluent waits instead of hardcoded thread sleeps. Dynamic waiting prevents flaky tests.

3. Design Scalable Test Data Strategies

Use external test data sources, generators and factories for dynamic test data. Avoid hardcoding.

4. Debug Tests Like Code

Leverage IDE debugger features, breakpoints, app logs etc. to fix tests easily.

5. Analyze Test Trends and Quality Metrics

Capture metrics on test coverage, pass %, flaky tests etc. and analyze trends to improve quality.

Other Tips Include:

• Ensuring element locators are unique and reliable
• Handling iframes, alerts, popups, DB validations in tests
• Integrating with test management tools like TestRail
• Running cross-browser, multi-device tests easily

These tips help you enhance end-to-end automation.

Now that you know how to setup, run, and optimize browser test automation – let‘s look at scaling it efficiently across an organization.

How To Scale Web Testing Automation Efficiently

As you expand test coverage, you need to scale automation efficiently. Here are my top recommendations:

1. Standardize Framework Structure & Coding

Create boilerplate code, templates and helper libraries that teams can build upon for faster test creation.

2. Centralize Test Assets in a Repository

Store test suites in a central repo for easy discoverability making them reusable across projects.

3. Align Automated Tests with CI/CD Pipelines

Embed test automation within developer commits and your software delivery lifecycle.

4. Containerize Tests Using Docker for Isolation

Run UI tests isolated from each other without environment conflicts.

5. Generate Detailed Metrics & Analytics

Use rich analytics for actionable insights – flaky tests, slow suites, environments issues etc.

6. Implement Visual Test Reports & Monitoring

Nice visual reports and dashboards for test status notifications help.

Other Scale Tips:

• Scheduling tests across distributed infrastructure
• Integrating automation framework with tools like Selenium Grid, BrowserStack
• Tracking ROI metrics for test automation

With the right strategy, you can efficiently scale test automation initiatives across your dev teams. This allows comprehensive and continuous testing.

Hopefully these insider tips give you a good understanding of efficiently leveraging test automation at an organizational level.

Now over to you!

Next Steps

I have equipped you with a 360 degree view of setting up and scaling test automation using Cucumber Selenium.

Here is what you can do next:

1. Start Small and Experiment

I would suggest starting with automating 2-3 critical test scenarios for your application as proof of concept.

2. Engage Teams Early

Involve developers, testers and product owners actively during test planning.

3 Learn With Examples

Take inspiration from open-source Cucumber+Selenium repo samples on GitHub.

4. Practice Cross Browser Testing

Evaluate real device cloud platforms like BrowserStack to easily test across 2000+ browsers.

I hope this detailed step-by-step expert guide gives you the confidence to automate browser testing like a pro using open-source tools like Cucumber and Selenium.

Feel free to reach out if you have any queries. Happy testing!

Author,
John Doe
Senior Test Automation Architect