Behavior-Driven Development (BDD) with Selenium and Cucumber

Behavior-Driven Development (BDD) is a methodology that bridges the gap between business and technical teams by emphasizing collaboration. It uses plain language to define application behavior, making it easier for non-technical stakeholders to contribute to the development process. Selenium and Cucumber are widely used together in BDD to automate web application testing.

This blog provides a detailed guide to implementing BDD using Selenium and Cucumber, including coding examples to help you get started.

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What is BDD?

BDD focuses on the behavior of an application from the end user's perspective. It uses scenarios written in Gherkin, a domain-specific language with a simple syntax:

• Given: Precondition or context.

• When: Action or event.

• Then: Outcome or result.

Example:

Feature: Login Functionality
  Scenario: Valid user logs in successfully
    Given the user is on the login page
    When the user enters valid credentials
    Then the user is redirected to the dashboard

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Tools Used

1. Selenium: Automates web browsers to test web applications.

2. Cucumber: Enables writing tests in plain English (Gherkin syntax).

3. Java: Programming language for writing test automation scripts.

4. JUnit/TestNG: Test framework to execute Cucumber tests.

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Setting Up Your Project

1. Create a Maven Project:

   • Add dependencies in pom.xml:

<dependencies>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-java</artifactId>
        <version>7.11.0</version>
    </dependency>
    <dependency>
        <groupId>io.cucumber</groupId>
        <artifactId>cucumber-junit</artifactId>
        <version>7.11.0</version>
    </dependency>
    <dependency>
        <groupId>org.seleniumhq.selenium</groupId>
        <artifactId>selenium-java</artifactId>
        <version>4.10.0</version>
    </dependency>
</dependencies>

2. Directory Structure:

   • src/test/java: For step definitions.

   • src/test/resources: For feature files.

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Writing a Feature File

Save this file as login.feature in src/test/resources/features:

Feature: Login Functionality

  Scenario: Valid user logs in successfully
    Given the user is on the login page
    When the user enters valid credentials
    Then the user is redirected to the dashboard

  Scenario: Invalid user cannot log in
    Given the user is on the login page
    When the user enters invalid credentials
    Then an error message is displayed

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Creating Step Definitions

Create a Java file LoginSteps.java in src/test/java/stepdefinitions:

package stepdefinitions;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import io.cucumber.java.en.*;

public class LoginSteps {
    WebDriver driver;

    @Given("the user is on the login page")
    public void userIsOnLoginPage() {
        System.setProperty("webdriver.chrome.driver", "path_to_chromedriver");
        driver = new ChromeDriver();
        driver.get("https://example.com/login");
    }

    @When("the user enters valid credentials")
    public void userEntersValidCredentials() {
        WebElement username = driver.findElement(By.id("username"));
        WebElement password = driver.findElement(By.id("password"));
        WebElement loginButton = driver.findElement(By.id("login"));

        username.sendKeys("validUser");
        password.sendKeys("validPassword");
        loginButton.click();
    }

    @Then("the user is redirected to the dashboard")
    public void userIsRedirectedToDashboard() {
        String expectedUrl = "https://example.com/dashboard";
        assert driver.getCurrentUrl().equals(expectedUrl);
        driver.quit();
    }

    @When("the user enters invalid credentials")
    public void userEntersInvalidCredentials() {
        WebElement username = driver.findElement(By.id("username"));
        WebElement password = driver.findElement(By.id("password"));
        WebElement loginButton = driver.findElement(By.id("login"));

        username.sendKeys("invalidUser");
        password.sendKeys("invalidPassword");
        loginButton.click();
    }

    @Then("an error message is displayed")
    public void errorMessageIsDisplayed() {
        WebElement error = driver.findElement(By.id("error"));
        assert error.isDisplayed();
        driver.quit();
    }
}

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Configuring the Runner Class

Create a Java file TestRunner.java in src/test/java/runners:

package runners;

import org.junit.runner.RunWith;
import io.cucumber.junit.Cucumber;
import io.cucumber.junit.CucumberOptions;

@RunWith(Cucumber.class)
@CucumberOptions(
    features = "src/test/resources/features",
    glue = "stepdefinitions",
    plugin = {"pretty", "html:target/cucumber-reports"},
    monochrome = true
)
public class TestRunner {
}

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Running Your Tests

1. Open a terminal.

2. Navigate to your project directory.

3. Run the following command:

mvn test

This will execute all scenarios defined in the login.feature file.

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Best Practices for BDD with Selenium and Cucumber

1. Keep Scenarios Simple: Use concise and descriptive steps in Gherkin.

2. Reuse Step Definitions: Avoid duplicating code by reusing steps where possible.

3. Parameterize Steps: Handle multiple inputs by parameterizing your Gherkin steps.

4. Organize Files: Maintain a clear structure for features, steps, and configurations.

5. Continuous Integration: Integrate Cucumber tests with CI/CD pipelines for automated execution.

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Conclusion

BDD with Selenium and Cucumber is a powerful combination for creating readable, maintainable, and effective test automation suites. By leveraging this approach, teams can foster collaboration, improve test coverage, and ensure high-quality software delivery. Start implementing BDD in your projects today and experience its benefits firsthand!

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Keywords: BDD, Selenium, Cucumber, Automation Testing, Behavior-Driven Development, Gherkin, Step Definitions, Test Automation Framework.