Introduction to Cucumber & Step Definitions

 

Writing Step Code

 

Learning Outcome

4

Use parameters and expressions in steps

3

Write basic step definition methods and Organize and reuse step code

2

Map Gherkin steps (Given/When/Then) to code

1

Understand purpose of step definitions in Cucumber

5

Integrate with frameworks like JUnit / TestNG

 

Recall

Basic understanding of Cucumber and BDD concepts

Knowledge of Gherkin syntax (Given, When, Then)

Fundamentals of a programming language (e.g., Java, Python, JavaScript)

Basics of OOP (classes, methods, variables)

Understanding of unit testing frameworks like JUnit or TestNG

Familiarity with IDEs (e.g., Eclipse IDE, IntelliJ IDEA)

Basic knowledge of automation testing concepts

Using Cucumber is like using Google Maps:

 

 

Gherkin steps (Given/When/Then) = The route you see (what should happen)

Step definitions = the actual driving instructions (how it happens)

Parameters = different destinations you enter each time

Reusable steps = common roads used again and again

JUnit / TestNG = the system that starts and monitors your journey

Gherkin shows the path, step definitions make the journey happen.

 

What is the purpose of step definitions in Cucumber

 

Step code is necessary to turn human-readable test scenarios into working automated tests.

 

Convert plain English into executable code
Steps written in Gherkin cannot run without step definitions

Bridge between feature files and automation logic
Connects “what to test” with “how to test”

Enable test execution
Without step code, scenarios cannot run

Support dynamic and reusable tests
Allows use of parameters and reusable logic

Improve maintainability
Centralizes automation logic for easy updates

Enable integration with tools
Works with JUnit / TestNG for execution and reporting

What is step definition?

A step definition in Cucumber is the core implementation layer that binds human-readable test scenarios written in Gherkin to executable automation code.

 

A step definition:

 

  • Matches a Gherkin step using annotations like @Given, @When, @Then

  • Executes automation code when the step is triggered

  • Sends input/output between feature file and system under test

 It acts like a translator + executor

 

How Mapping Works

 

Example Gherkin:

Given user is on login page

 

 

public void user_is_on_login_page()
{
   driver.get("https://example.com/login");
}

Mapped step definition:

@Given("user is on login page")

 

Matching happens using:

 

Exact text match

Cucumber Expressions

Regular Expressions

Workflow of Step Definitions

 

1. Write Feature File (Gherkin)

You first write test scenarios in plain English using Gherkin.

You create a Java class to implement step definitions.

 

Each step in the feature file is connected to a method using annotations.

 

@Given("user is on login page")

 

public void openLoginPage() 
{
   // open browser and navigate
}

2. Create Step Definition Class

3. Map Gherkin Steps to Methods

@When("user enters valid credentials")

 

public void enterCredentials() 
{
   // enter username/password
}

@Then("user should be logged in")

 

public void verifyLogin() 
{
   // validate login success
}

 This is the core role of step definitions

 

Inside each step method:

 

  • Selenium actions (UI automation)

  • API calls (if backend testing)

  • Assertions for validation

You configure execution using JUnit or TestNG.

 

4. Add Automation Logic

5. Create Test Runner (JUnit/TestNG)

 Example:

 

driver.get("https://app.com/login");

 

@RunWith(Cucumber.class)
@CucumberOptions(
   features = "src/test/resources/features",
   glue = "stepDefinitions"
)

When you run the test:

 

6. Execution Flow Starts

7. Result Generation

After execution:

 

Parameters and expressions in steps

Parameters and expressions allow step definitions to accept dynamic values from Gherkin steps instead of hardcoded data.

 

1. Parameters

 

Parameters are input values passed from feature files into step definition methods.

 

 Example:

 

When user enters "admin" and "1234"

Step definition:

 

@When("user enters {string} and {string}")

public void enterCredentials(String username, String password) 
{
   System.out.println(username);
   System.out.println(password);
}

  • "admin" → username

  • "1234" → password

2. Expressions

Expressions define how Cucumber identifies and captures values from steps.

 

Cucumber Expressions

 

 Example:

 

@When("user adds {int} and {int}")

 

public void add(int a, int b) 
{
   System.out.println(a + b);
}

Integrating Cucumber with JUnit / TestNG

In Cucumber, step definitions alone cannot run. They must be executed through a test runner framework like JUnit or TestNG.

Integration with JUnit

 

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/report.html"}
)
public class TestRunner {
}

✔ Test Runner Class:

Key Points :

  • @RunWith(Cucumber.class) → tells JUnit to run Cucumber

  • features → path of feature files

  • glue → step definition package

  • plugin → reporting

import io.cucumber.testng.AbstractTestNGCucumberTests;
import io.cucumber.testng.CucumberOptions;

@CucumberOptions(
   features = "src/test/resources/features",
   glue = "stepDefinitions",
   plugin = {"pretty", "html:target/report.html"}
)
public class TestRunner extends AbstractTestNGCucumberTests {
}

Key Points :

  • Extends AbstractTestNGCucumberTests

  • No @RunWith needed

  • Better for parallel execution

✔ Test Runner Class:

Integration with TestNG

Summary

4

3

Use annotations (@Given, @When, @Then) for step definitions

2

Map each step to corresponding Java methods

1

5

Apply parameters & expressions for reusable steps

 

Integrate with JUnit/TestNG for execution and reporting

Link Gherkin steps (Given/When/Then) to automation code

Quiz

 What is the main purpose of step definitions in Cucumber?

A. To write test reports

B. To connect Gherkin steps to automation code

C. To run the browser

D. To create test data

 

Quiz-Answer

 What is the main purpose of step definitions in Cucumber?

A. To write test reports

B. To connect Gherkin steps to automation code

C. To run the browser

D. To create test data

 

Introduction to Cucumber & Step Definitions(Writing Step Code)

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Introduction to Cucumber & Step Definitions(Writing Step Code)

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