15 Cucumber BDD Framework Interview Questions and Answers

Cucumber is a popular Behavior-Driven Development (BDD) framework that facilitates collaboration between developers, testers, and business stakeholders. By allowing test scenarios to be written in plain language, Cucumber bridges the gap between technical and non-technical team members, ensuring that everyone has a clear understanding of the project requirements. This approach not only improves communication but also enhances the overall quality of the software being developed.

This article provides a curated selection of interview questions designed to test your knowledge and proficiency with the Cucumber BDD framework. Reviewing these questions will help you gain a deeper understanding of Cucumber’s features and best practices, ensuring you are well-prepared for your upcoming interview.

Cucumber BDD Framework Interview Questions and Answers

1. Describe the structure of a Cucumber feature file.

A Cucumber feature file is a plain text file that describes the features and scenarios to be tested using specific keywords:

• Feature: Defines the feature under test with a high-level description.
• Scenario: Describes a specific test case or scenario with a sequence of steps.
• Given, When, Then, And, But: Define the steps in a scenario, describing the initial context, the event or action, and the expected outcome.

Example:

Feature: User login

  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When the user enters valid credentials
    Then the user should be redirected to the dashboard

  Scenario: Unsuccessful login with invalid credentials
    Given the user is on the login page
    When the user enters invalid credentials
    Then an error message should be displayed

2. How do you define a scenario outline in Cucumber?

A scenario outline in Cucumber allows you to run the same scenario multiple times with different sets of input data, useful for data-driven testing. It defines a template for the scenario and provides different data sets in a tabular format.

Example:

Feature: Login functionality

  Scenario Outline: Successful login with valid credentials
    Given the user is on the login page
    When the user enters "<username>" and "<password>"
    And clicks the login button
    Then the user should be redirected to the dashboard

    Examples:
      | username | password |
      | user1    | pass1    |
      | user2    | pass2    |
      | user3    | pass3    |

3. Write a Gherkin syntax for a login feature with valid and invalid credentials.

Gherkin syntax in Cucumber defines test cases in a natural language format. Below is an example for a login feature with valid and invalid credentials.

Feature: Login Feature

  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When the user enters a valid username and password
    And clicks the login button
    Then the user should be redirected to the dashboard

  Scenario: Unsuccessful login with invalid credentials
    Given the user is on the login page
    When the user enters an invalid username or password
    And clicks the login button
    Then an error message should be displayed

4. Explain the purpose of step definitions in Cucumber.

Step definitions in Cucumber link Gherkin feature files to the underlying test code. They define the actions for each step in a Gherkin scenario.

Example:

// Gherkin feature file
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 definition file
import cucumber.api.java.en.Given;
import cucumber.api.java.en.When;
import cucumber.api.java.en.Then;

public class LoginSteps {

    @Given("the user is on the login page")
    public void userIsOnLoginPage() {
        // Code to navigate to the login page
    }

    @When("the user enters valid credentials")
    public void userEntersValidCredentials() {
        // Code to enter valid credentials
    }

    @Then("the user should be redirected to the dashboard")
    public void userIsRedirectedToDashboard() {
        // Code to verify redirection to the dashboard
    }
}

5. Write a step definition for a Gherkin step that includes a parameter.

A step definition with a parameter allows flexibility and reusability by accepting dynamic values.

Example:

Given I have a user with name "John"

Step definition in Java:

import io.cucumber.java.en.Given;

public class StepDefinitions {

    @Given("I have a user with name {string}")
    public void i_have_a_user_with_name(String name) {
        System.out.println("User name is: " + name);
    }
}

6. Explain the concept of background in Cucumber.

The background in Cucumber defines steps common to all scenarios in a feature file, executed before each scenario to avoid repetition.

Example:

Feature: User login

  Background:
    Given the user is on the login page

  Scenario: Successful login
    When the user enters valid credentials
    Then the user should be redirected to the dashboard

  Scenario: Unsuccessful login
    When the user enters invalid credentials
    Then the user should see an error message

7. How do you integrate Cucumber with JUnit or TestNG?

To integrate Cucumber with JUnit or TestNG, set up your project with the necessary dependencies and configure a test runner class.

For JUnit:

// Add dependencies in pom.xml
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-java</artifactId>
    <version>6.10.4</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-junit</artifactId>
    <version>6.10.4</version>
    <scope>test</scope>
</dependency>

// Test runner class
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")
public class TestRunner {
}

For TestNG:

// Add dependencies in pom.xml
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-java</artifactId>
    <version>6.10.4</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>io.cucumber</groupId>
    <artifactId>cucumber-testng</artifactId>
    <version>6.10.4</version>
    <scope>test</scope>
</dependency>

// Test runner class
import io.cucumber.testng.AbstractTestNGCucumberTests;
import io.cucumber.testng.CucumberOptions;

@CucumberOptions(features = "src/test/resources/features", glue = "stepDefinitions")
public class TestRunner extends AbstractTestNGCucumberTests {
}

8. Write a step definition that reads data from an external file.

To read data from an external file in a step definition, use standard file I/O operations.

Example in Java:

import io.cucumber.java.en.Given;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.IOException;

public class StepDefinitions {

    @Given("I read data from {string} file")
    public void i_read_data_from_file(String fileName) throws IOException {
        String data = new String(Files.readAllBytes(Paths.get(fileName)));
        System.out.println(data);
    }
}

9. How do you generate Cucumber reports and what types of reports are available?

Cucumber reports provide insights into test execution. Configure the framework to produce output in the desired format using Cucumber options.

Example:

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

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

Report formats include:

• Pretty: Prints the Gherkin source with additional colors and stack traces for errors.
• HTML: Generates an HTML report.
• JSON: Generates a JSON report.

10. Explain the concept of data tables in Cucumber and how to use them.

Data tables in Cucumber allow passing multiple sets of data to a single step definition, useful for repetitive testing with different inputs.

Example:

Feature: User Login

  Scenario Outline: Successful login with valid credentials
    Given the user is on the login page
    When the user enters the following credentials
      | username | password |
      | user1    | pass1    |
      | user2    | pass2    |
    Then the user should be redirected to the homepage

Step definition:

@Given("the user enters the following credentials")
public void the_user_enters_the_following_credentials(DataTable dataTable) {
    List<Map<String, String>> credentials = dataTable.asMaps(String.class, String.class);
    for (Map<String, String> credential : credentials) {
        String username = credential.get("username");
        String password = credential.get("password");
        // Code to enter username and password
    }
}

11. Write a step definition that uses a data table to validate multiple user details.

Step definitions map Gherkin steps to code. Data tables allow passing a list of values to a step definition, useful for validating multiple user details.

Example:

import io.cucumber.datatable.DataTable;
import io.cucumber.java.en.Then;
import java.util.List;
import java.util.Map;
import static org.junit.Assert.assertEquals;

public class UserValidationSteps {

    @Then("the following user details should be validated")
    public void validateUserDetails(DataTable dataTable) {
        List<Map<String, String>> userDetails = dataTable.asMaps(String.class, String.class);

        for (Map<String, String> user : userDetails) {
            String username = user.get("username");
            String email = user.get("email");
            String role = user.get("role");

            // Perform validation logic here
            assertEquals("ExpectedUsername", username);
            assertEquals("ExpectedEmail", email);
            assertEquals("ExpectedRole", role);
        }
    }
}

12. Explain how to implement parallel test execution in Cucumber.

Parallel test execution in Cucumber can be achieved by leveraging the capabilities of the underlying test runner, such as JUnit or TestNG.

For JUnit, use the cucumber-junit library with the maven-surefire-plugin or maven-failsafe-plugin:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.22.2</version>
    <configuration>
        <parallel>methods</parallel>
        <threadCount>4</threadCount>
    </configuration>
</plugin>

For TestNG, configure parallel execution in the testng.xml file:

<suite name="Cucumber Suite" parallel="tests" thread-count="4">
    <test name="Cucumber Test">
        <classes>
            <class name="com.example.RunCucumberTest"/>
        </classes>
    </test>
</suite>

13. What are the best practices for writing maintainable feature files?

When writing maintainable feature files, follow best practices to ensure clarity and ease of maintenance:

• Keep Scenarios Simple and Focused: Each scenario should test a single behavior or functionality.
• Use Descriptive Titles: Scenario titles should clearly describe the behavior being tested.
• Maintain Consistent Language: Use consistent terminology and phrasing across all feature files.
• Reuse Steps: Create reusable step definitions to avoid duplication.
• Organize Feature Files Logically: Group related scenarios into feature files based on functionality or user stories.
• Use Background Wisely: The Background section should contain common steps shared by all scenarios in a feature file.
• Document Assumptions and Preconditions: Clearly state any assumptions or preconditions required for the scenarios.
• Review and Refactor Regularly: Periodically review and refactor feature files to ensure they remain clean and maintainable.

14. Explain the role of tags in Cucumber and how they can be used effectively.

Tags in Cucumber group and filter scenarios for execution. They categorize tests, making it easier to manage and run specific subsets. Tags are defined by prefixing a word with the “@” symbol and placing it above the Feature or Scenario keyword.

Example:

@smoke
Feature: User Login

  @positive
  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When the user enters valid credentials
    Then the user should be redirected to the dashboard

  @negative
  Scenario: Unsuccessful login with invalid credentials
    Given the user is on the login page
    When the user enters invalid credentials
    Then an error message should be displayed

To run only the positive scenarios, use:

cucumber --tags @positive

15. How do you integrate Cucumber with Continuous Integration (CI) tools like Jenkins?

Integrating Cucumber with Continuous Integration (CI) tools like Jenkins involves setting up the environment with necessary plugins, configuring the Jenkins job to check out code, and running Cucumber tests using a build tool like Maven or Gradle. Finally, configure Jenkins to publish the Cucumber test results using the Cucumber Reports plugin.