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Behaviour Driven Development

By Srinesh Nisala

1. Introduction to Cucumber​

Objective: Explore Cucumber as a BDD tool.

Key Topics​

  • What is Cucumber?
    • Open-source tool supporting BDD with plain-language specifications.
    • Uses Gherkin syntax to write scenarios.
  • Gherkin Syntax Basics:
    • Keywords:
      • Feature: description of a software feature
      • Scenario: example that illustrates a business rule
      • Given: initial context of the system
      • When: describe an event, or an action
      • Then: describe an expected outcome
  • Tool Integration: Works with Java, Ruby, JavaScript, etc., via frameworks like JUnit or Selenium.
Scenario: eat 5 out of 12
  Given there are 12 cucumbers
  When I eat 5 cucumbers
  Then I should have 7 cucumbers

2. Hands-On Demo: Building a Feature with Cucumber​

Objective: Implement a BDD workflow using Cucumber.

Pre-requisites​

Understanding the project structure​

  • Explain package.json
  • Explain feature
  • Explain step definition

Exercise​

  1. Parameterize the addition test without hard-coded values
  2. Write a scenario for subtraction
  3. Write step definition for subtraction
  4. Implement subtraction feature to calculator
  5. Instead of hard-coded values, parameterize the values

3. Introduction to BDD​

Objective: Understand the philosophy and purpose of BDD.

Key Topics​

  • What is BDD?
    • Agile methodology bridging technical and non-technical stakeholders.
    • Evolved from TDD (Test-Driven Development) but focuses on behavior over tests.
    • Key Goal: Ensure software meets business requirements through collaboration.
  • Why BDD?
    • Reduces misunderstandings between developers, testers, and product owners.
    • Creates living documentation (executable specifications).
    • Encourages iterative, example-driven development.
  • BDD vs. TDD:
    • TDD: "Write tests first, then code." Focuses on code correctness.
    • BDD: "Define behavior first, then automate." Focuses on business value.

4. References​