Beginner Chapter 1 · 8 min read

Introduction to BDD & Cucumber

Understand Behavior-Driven Development, the Gherkin language, how Cucumber bridges business and engineering, and why BDD matters.

What is Behavior-Driven Development?

BDD is a collaborative approach where business stakeholders, developers, and testers define application behavior using a shared, plain-language format before code is written. The result: executable specifications that serve as both tests and living documentation.

The Three Amigos

BDD starts with a Three Amigos session — a Product Owner describes a feature, a Developer asks about edge cases, and a Tester challenges with negative scenarios. Together they write examples in Gherkin that become automated tests.

Gherkin — The Language of Cucumber

Gherkin uses keywords everyone understands: Feature, Scenario, Given (precondition), When (action), and Then (expected outcome). Each keyword maps to a step definition in code.

Cucumber Ecosystem

Java — Cucumber-JVM with Maven, TestNG/JUnit, and Selenium
Python — Behave (the most popular Python BDD framework, Cucumber-compatible syntax)

Benefits of BDD

A single source of truth for requirements, tests, and documentation
Non-technical stakeholders can read and even write scenarios
Early defect detection through concrete examples
Reduced miscommunication between business and tech teams

# src/test/resources/features/login.feature
Feature: User Login
  As a registered user
  I want to log into my account
  So that I can access the dashboard

  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When the user enters username "admin" and password "admin123"
    And the user clicks the login button
    Then the user should be redirected to the dashboard
    And the welcome message should display "Welcome, Admin"

  Scenario: Failed login with invalid credentials
    Given the user is on the login page
    When the user enters username "wrong" and password "wrong"
    And the user clicks the login button
    Then an error message "Invalid credentials" should be displayed

# features/login.feature
Feature: User Login
  As a registered user
  I want to log into my account
  So that I can access the dashboard

  Scenario: Successful login with valid credentials
    Given the user is on the login page
    When the user enters username "admin" and password "admin123"
    And the user clicks the login button
    Then the user should be redirected to the dashboard
    And the welcome message should display "Welcome, Admin"

  Scenario: Failed login with invalid credentials
    Given the user is on the login page
    When the user enters username "wrong" and password "wrong"
    And the user clicks the login button
    Then an error message "Invalid credentials" should be displayed

Cucumber BDD Beginner Introduction to BDD & Cucumber

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Written by PV