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Table of contents
1.
Introduction
2.
What is Cucumber?
3.
Prerequisite
4.
What is BDD?
5.
Which Language is Used in Cucumber?
6.
Basic Terms of Cucumber
6.1.
Feature Files
6.2.
Scenarios
6.3.
Steps
6.4.
Step Definitions
6.5.
Tags
6.6.
Hooks
7.
Feature
8.
How BDD Works in Cucumber Automation?
8.1.
Here’s how BDD works in Cucumber
8.1.1.
Define Features and Scenarios
8.1.2.
Write Step Definitions
8.1.3.
Execute Tests
8.1.4.
Review Results
9.
Advantages of Cucumber Software
9.1.
Enhanced Communication
9.2.
Living Documentation
9.3.
Focus on User Experience
9.4.
Facilitates Test Automation
9.5.
Cross-Platform Testing
9.6.
Reduces Redundancy
9.7.
Continuous Integration (CI) Friendly
10.
Software Tools Supported by Cucumber
10.1.
Selenium WebDriver
10.2.
JUnit and TestNG
10.3.
Appium
10.4.
Spring Framework
10.5.
Ruby on Rails
10.6.
REST-assured
10.7.
Maven and Gradle
10.8.
Git
11.
Frequently Asked Questions
11.1.
Can I use Cucumber with languages other than Java?
11.2.
Is Cucumber only for web application testing?
11.3.
How does Cucumber fit into Agile methodologies?
12.
Conclusion
Last Updated: Mar 27, 2024
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What is Cucumber?

Author Sinki Kumari
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Introduction

Cucumber is a software tool used by developers & testers for running automated acceptance tests crafted in plain language. This tool bridges the communication gap between tech & non-tech team members by allowing them to collaborate & understand the project's features. 

What is Cucumber?

Through this article, you'll learn the essentials of Cucumber, explore its syntax & terms, & learn about Behavior-Driven Development (BDD). We'll walk you through the basics, from setting up Cucumber to understanding its key advantages & supported tools.

What is Cucumber?

Cucumber is a testing tool that supports Behavior-Driven Development (BDD), a development approach that encourages collaboration among developers, QA, and non-technical or business participants in a software project. It allows users to describe how software should behave in plain, understandable English. This not only aids in the clear communication of project features but also serves as living documentation and a skeleton for automated tests.

Cucumber reads executable specifications written in plain language and validates that the software does what those specifications say. The specifications consist of multiple examples or scenarios. Each scenario is a list of steps for Cucumber to work through. Cucumber allows the execution of feature documentation written in business-facing text.

Here's a simple example of a Cucumber scenario:

  • Feature: Login functionality
     
  •  Scenario: User successfully logs in with valid credentials

    Given the user is on the login page

    When the user enters valid credentials

    Then the user is redirected to the homepage

This example outlines a feature of the login functionality, describing a scenario where a user logs in successfully with valid credentials. Each step ('Given', 'When', 'Then') corresponds to a piece of code that will execute the action described by the step.

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Prerequisite

Before understanding Cucumber & its applications, it's essential to have a foundational setup. Firstly, you need to have Java installed on your system since Cucumber runs on the JVM (Java Virtual Machine). You can verify this by running java -version in your command line. If Java is not installed, you'll need to download & install it from the official Java website.

Secondly, you'll require an IDE (Integrated Development Environment) like IntelliJ IDEA or Eclipse to write your test cases. These environments provide plugins for Cucumber, making it easier to write & run your tests.

Lastly, you should have Maven or Gradle set up in your project for managing dependencies. This will allow you to easily add Cucumber to your project by including it in your pom.xml (for Maven) or build.gradle (for Gradle) file.

Here's an example of how to add Cucumber to your Maven project:

<dependencies>
    <!-- Cucumber -->
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-java</artifactId>
        <version>6.10.4</version>
    </dependency>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-junit</artifactId>
        <version>6.10.4</version>
        <scope>test</scope>
    </dependency>
</dependencies>


This snippet adds Cucumber to your project, enabling you to start writing your BDD tests.

What is BDD?

Behavior-Driven Development (BDD) is a software development approach that emphasizes collaboration among developers, QA professionals, and non-technical or business participants in a software project. BDD focuses on obtaining a clear understanding of desired software behavior through discussion with stakeholders. It narrows the gap between business requirements and technical implementation by expressing these requirements as concrete examples.

BDD encourages writing software features in a human-readable format, often using Given-When-Then statements, which describe a specific scenario or behavior the software should exhibit. This method allows for the creation of automated tests directly from these descriptions, ensuring that the software meets the business requirements.

For instance, consider a feature where a user needs to withdraw money from an ATM:

  • Feature: Withdraw Money
     
  • Scenario: Account has sufficient funds

    Given the user's account balance is $100

    When the user attempts to withdraw $20

    Then the withdrawal should be successful

    And the account balance should be $80

In this BDD scenario, the behavior of the ATM when the account has enough funds is clearly described, making it easy for everyone involved to understand what the software should do.

Which Language is Used in Cucumber?

Cucumber tests are written in Gherkin, a plain English text language, which allows for easy understanding and readability. Gherkin is designed to be non-technical and human-readable, and it enables the documentation of software functionalities without detailing how that functionality is implemented.

Gherkin follows a simple set of keywords: Feature, Scenario, Given, When, Then, And, But, which are the building blocks of Cucumber test scenarios. These keywords enable the definition of complex software behaviors without writing a single line of code.

Here’s a brief overview of these keywords:

  • Feature: Describes the feature you are testing.
     
  • Scenario: Describes a specific scenario under which a feature is tested.
     
  • Given: Provides context for the scenario, such as preconditions or initial states.
     
  • When: Specifies the set of actions that trigger the scenario.
     
  • Then: Describes the expected outcome after the scenario's execution.
     

And, But: Used to add more steps to your Given, When, or Then steps.

For example, to describe a login feature, you might write:

Feature: User Login

  •   Scenario: Logging in with correct credentials
     
  •     Given I am on the login page
     
  •     When I enter the correct username and password
     
  •     Then I should be redirected to the dashboard

This Gherkin syntax provides a clear, concise, and readable format, which is ideal for collaboration among technical and non-technical team members.

Basic Terms of Cucumber

Understanding the basic terminology of Cucumber is crucial for effectively utilizing its capabilities. Here are some of the key terms:

Feature Files

These are files where your specifications or requirements are written in Gherkin language. Each file typically represents one feature of your application and contains one or more scenarios.

Scenarios

A scenario is a written description of a feature's functionality from one or more user perspectives. It consists of a series of steps to achieve or verify something within the feature.

Steps

Individual steps are the building blocks of a scenario, following the Given-When-Then format. Each step is matched to a step definition in your test code.

Step Definitions

These are Java, Ruby, or other language methods that link the steps in your scenarios to code that carries out the action described by the step. When Cucumber runs a step in a scenario, it will look for a matching step definition to execute.

Tags

Tags are a great way to organize your features and scenarios. You can use tags to group tests into categories, such as @smoke or @regression, making it easier to run a subset of tests.

Hooks

Hooks are blocks of code that can run before or after each scenario, or even before and after all of your scenarios. They are useful for setting up or tearing down test environments.

For example, a simple scenario in a feature file might look like this:

Feature

 User Authentication

 @login

  Scenario: Successful login with valid credentials

    Given I am on the login page

    When I enter valid credentials

    Then I should be redirected to the homepage

And a corresponding step definition in Java might be:

@Given("I am on the login page")
public void i_am_on_the_login_page() {
    // code to navigate to the login page
}
@When("I enter valid credentials")
public void i_enter_valid_credentials() {
    // code to enter login credentials
}
@Then("I should be redirected to the homepage")
public void i_should_be_redirected_to_the_homepage() {
    // code to check the page redirection
}


Understanding these terms and their roles within Cucumber will help you write clearer, more effective tests.

How BDD Works in Cucumber Automation?

Behavior-Driven Development (BDD) in Cucumber automation revolves around the idea of writing tests based on the expected behavior of the application, which is described in a way that's understandable to all stakeholders. This approach ensures that all members of a team, including non-technical members, can participate in the discussion about what the software should do and how it should work.

Here’s how BDD works in Cucumber

Define Features and Scenarios

Start by defining the features of your application in Gherkin language within feature files. Each feature contains scenarios, which are examples of how the feature should behave under different conditions.

Write Step Definitions

For each step in your scenarios, you write a step definition in a programming language like Java. These step definitions are the actual code that will be executed when the step is run.

Execute Tests

When you run Cucumber, it reads the feature files, matches each step in the scenarios to a step definition, and executes the code within those step definitions.

Review Results

After the tests run, Cucumber outputs the results, showing which scenarios and steps passed or failed. This feedback loop is crucial for understanding the behavior of the application and for ensuring that the software meets the business requirements.

Let's consider an example scenario for adding a book to a wishlist:

  • Feature: Wishlist Feature
     
  • Scenario: Add a book to the wishlist

    Given I am logged in as a user

    And I am on the page of "The Great Gatsby"

    When I click on "Add to Wishlist"

    Then "The Great Gatsby" should be in my wishlist

For each step in this scenario, there would be a corresponding step definition, which could look something like this in Java:

@Given("^I am logged in as a user$")
public void i_am_logged_in_as_a_user() {
    // Code to log in the user
}
@And("^I am on the page of \"([^\"]*)\"$")
public void i_am_on_the_page_of(String bookName) {
    // Code to navigate to the page of the book
}
@When("^I click on \"([^\"]*)\"$")
public void i_click_on(String button) {
    // Code to click on the button
}
@Then("^\"([^\"]*)\" should be in my wishlist$")
public void should_be_in_my_wishlist(String bookName) {
    // Code to verify the book is in the wishlist
}

This example illustrates how BDD in Cucumber automation bridges the gap between specification and implementation, ensuring that the software behaves as expected.

Advantages of Cucumber Software

Cucumber offers several benefits that make it a popular choice for behavior-driven development (BDD). Some of these advantages include:

Enhanced Communication

Cucumber's use of Gherkin, a natural language format, allows team members with varying technical expertise to understand the functionalities being tested. This promotes better collaboration and clarity in project requirements among developers, testers, and business stakeholders.

Living Documentation

The feature files in Cucumber serve as both documentation and a test suite. This means the documentation is always up to date with the application's current capabilities, providing a reliable source of information for how features should work.

Focus on User Experience

By defining tests in terms of user behaviors and outcomes, Cucumber helps teams keep the user's experience at the forefront of development, leading to more user-friendly applications.

Facilitates Test Automation

Cucumber seamlessly integrates with various testing frameworks like Selenium, allowing for easy automation of web application testing. This integration helps in covering a wide range of testing scenarios, from simple unit tests to complex UI tests.

Cross-Platform Testing

Cucumber supports various programming languages and platforms, making it versatile for different types of projects. Whether you're developing a web, mobile, or desktop application, Cucumber can be adapted to meet your testing needs.

Reduces Redundancy

With its reusable step definitions, Cucumber reduces the need to write duplicate code for similar test scenarios. This not only saves time but also makes the test suite easier to maintain.

Continuous Integration (CI) Friendly

Cucumber tests can be easily integrated into CI pipelines, enabling teams to automatically run tests with every build. This helps in identifying and fixing issues early in the development cycle.

Software Tools Supported by Cucumber

Cucumber is designed to work seamlessly with a wide range of software tools, enhancing its versatility and applicability across different stages of software development and testing. Here are some key tools and frameworks that integrate well with Cucumber:

Selenium WebDriver

For web application testing, Selenium WebDriver can be used in conjunction with Cucumber to automate browser actions and validate web page functionalities against specified behaviors.

JUnit and TestNG

These are popular frameworks for unit testing in Java. Cucumber can integrate with both to manage test cases and generate reports, providing a structured way to execute BDD scenarios.

Appium

For mobile application testing, Appium offers automation for iOS and Android apps. Cucumber's compatibility with Appium allows for the execution of BDD scenarios on mobile devices, ensuring that apps behave as expected on various platforms.

Spring Framework

For applications built with Spring, Cucumber can be used to test the application's behavior in a Spring context, allowing for dependency injection and the use of Spring components in tests.

Ruby on Rails

Cucumber originally started as a tool for Ruby testing. It works well with Ruby on Rails for testing web applications, making it a good choice for BDD in Ruby projects.

REST-assured

For testing RESTful web services, REST-assured provides a fluent Java DSL. Cucumber can be used alongside REST-assured to write BDD scenarios for API testing.

Maven and Gradle

These build and dependency management tools for Java can be used to manage Cucumber dependencies, compile test code, and run Cucumber features as part of the build process.

Git

While not a testing tool, Git is essential for version control. Cucumber feature files and step definitions can be stored and versioned in a Git repository, facilitating collaboration among team members.

By integrating with these tools, Cucumber enhances its capability to support a wide range of testing needs, from web and mobile to API testing, making it a versatile choice for implementing BDD in various project environments.

Frequently Asked Questions

Can I use Cucumber with languages other than Java?

Yes, Cucumber supports multiple programming languages including Ruby, JavaScript, and Python. This flexibility allows you to write step definitions in the language that best suits your project.

Is Cucumber only for web application testing?

No, Cucumber can be used for testing web, mobile, desktop, and even API applications. Its integration with tools like Selenium, Appium, and REST-assured extends its testing capabilities beyond just web applications.

How does Cucumber fit into Agile methodologies?

Cucumber complements Agile practices by facilitating collaboration through its use of plain language to define test scenarios. This makes it easier for team members, including those with non-technical backgrounds, to participate in defining and understanding the application's behavior.

Conclusion

Cucumber stands out as a powerful tool for implementing Behavior-Driven Development (BDD) in software projects. Its use of plain language to describe software behaviors makes it accessible to both technical and non-technical team members, fostering better communication and collaboration. The ability to integrate with a wide range of testing tools and frameworks extends its applicability to various types of applications, from web and mobile to APIs. By adopting Cucumber, teams can ensure their software not only meets technical requirements but also delivers the user experiences that stakeholders envision. With Cucumber, you're not just writing tests; you're defining the blueprint for your application's functionality and ensuring it aligns with your users' needs and expectations.

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