Behavior Driven Development

DHAWAL JOSHI
AJIT KUMAR NARAYANAN
MAKING BDD FUN WITH CUCUMBER, JASMINE AND …

BDD
 TDD
• Write Tests first
• Watch it fail
• Write enough code to make the test pass
• Continue
 But, soon
• Where do I start ?, What should I test
• What should I call the tests
• Why is that test failing and what user stories does it impact ?
 BDD
 = TDD + Stakeholder Value + Collaboration + Behaviour
 Usually written on top of DSLs that resemble natural language ( Only to address Collaboration)

Who needs to know BDD?
Product Owner / Stakeholder Developer Tester

Principles
 Think Behaviour & everyone speaks the same language
 And about stakeholder value
 Enough is enough

Traditional Way
Product Owner /
Stakeholder
Developer
Tester
User Stories
Clarifications
Specifications, Design
Test Case Document
There are many
Bugs !
But, see it is in
The test case
document
But, it was never
Specified …
That’s correct. It
Is the right spec !
Well, you never
Told me
I told the tester.
Aren’t you guys in one
Team ???

BDD Way
Product Owner /
Stakeholder
DeveloperTester
User Stories
Clarifications
SpecificationsTest Case Document
We better start
collaborating better
and talk same language
We better start
We better start
Ubiquitous Language
1: Think Behaviour & everyone speaks the same language

Value
2: Stakeholder value
Product Owner /
Stakeholder
In Order to [Business Value]
As a [Role]
I want to [Feature]
1. Protect Revenue
2. Increase Revenue
3. Manage Cost

How much is Enough ?
3: Enough is Enough
1. No Over engineering
2. No Overdoing { planning, Analysis and Design }
3. There is no such thing as a perfect software

Ubiquitous Language
A Language structured around the domain model that everyone in the team
understands.
A Language capable to express a feature, its business value and behaviour (
Behaviour = Context Action Outcome )

Gherkin ?
1. Business Readable DSL that expresses the ‘what’ of the software without specifying the
‘how’ i.e it describes Behaviour
2. Serves 2 Purposes : Documentation + Automated testing
3. Line oriented language like python or YAML; Uses indentation to define structure

Gherkin ?
Feature: Search courses
In order to ensure better utilization of courses
Potential students should be able to search for courses
Scenario: Search by topic
Given there are 240 courses which do not have the topic "biology"
And there are 2 courses A001, B205 that each have "biology" as one of the topics
When I search for "biology"
Then I should see the following courses:
| Course code |
| A001 |
| B205 |
Context
Action
Outcome
Behavior

Cucumber ?
1. Is a Tool that executes plain-text functional descriptions as automated tests
2. Understands the ‘Gherkin’ Language
3. Itself is written in Ruby, but can be used for several languages
4. Has several language specific variations : E.g : Cucumber.js , Cucumber JVM etc …

Cucumber ?
Feature: Search courses
In order to ensure better utilization of courses
Potential students should be able to search for courses
Scenario: Search by topic
Given there are 240 courses which do not have the topic "biology"
And there are 2 courses A001, B205 that each have "biology" as one of the topics
When I search for "biology"
Then I should see the following courses:
| Course code |
| A001 |
| B205 |
Feature
Step Definitions ( Regex)
Scenario ( 5- 25)

Cucumber ?
Product Owner /
Stakeholder
DeveloperTester
Features
Step Definitions

Cucumber : Organizing your features
Project Root
features
support
step_defenitions
Thegreatest.feature
Theultimate.feature
Thegreatest_steps.rb
Theultimate_steps.rb
env.rb

step definition
Given there are 200 elements in the stack Given /^there are (d+) elements in the queue’ do
#DO SOMETHING HERE
@stack= Stack.new
200.times do |i|
@stack.push(‘item’ + i.to_s)
end
end

step definition
Given there are 200 elements in the stack
When I add another element
When /^I add another element’ do
@stack.push ‘itemanother’
end

step definition
Given there are 200 elements in the stack
When I add another element
Then there should be 201 elements
Then /^There should be (d+) elements’ do
@stack.count.should == 201
end

Cucumber & Agile test matrix
Cucumber / Variants

BUT, NOT ALL Q2 TESTS ARE API BASED
TESTS

ENTER CAPYBARA, SELENIUM, WEBRAT,
ZOMBIE.JS AND 100 OTHER WEB APP
TEST FRAMEWORKS

CAPYBARA
.is a library that can be used with cucumber to write tests that also need javascript support.
SELENIUM
… automates web browsers across many platform
WEBRAT
… allows to quickly write robust and thorough acceptance tests for a web application. By
leveraging the DOM, it can run tests similarly to an in-browser testing solution without the
associated performance hit (and browser dependency)

Jasmine
1. Yet another BDD framework for testing your java script code
2. Evolved from Rspec
3. Suited for Q1 Tests
4. Can run in browser or server-side environments like node.js
describe (“<UNIT NAME >”, function() {
describe(“<BEHAVIOUR>”, function () {
it(“<SHOULD DO WHAT >, function (){
});
});
});

Jasmine
describe (“Customer Model”, function() {
var cust = new Customer();
describe(“When saved without an ID”, function () {
cust.id = null;
it(“should throw an ID cannot be null exception”, function (){
expect(custid.save()).toThrow(“IDCannotbeNull”);
});
});
});
Your behavior reads : “Customer Model when saved without an ID should throw an ID cannot
be null exception”
Spec File

Cucumber : Organizing your Specs
Project Root
spec
SomeUnitspec.js
models
Customermodelspec.js
SpecRunner.html

Jasmine & Agile test matrix
Cucumber / Variants

Typical Flow
Write the Features
(DEV, PO, QE)
Refine Features
(DEV, PO, QE)
Add Step Definitions
(DEV, QE)
Write the code
/ UI that you wished
you had
(QE/Dev)
RunTest
Do you want to add/modify a unit ?
Describe Behavior
(Dev , Verified by Arch)RunTestWrite enough to
Make test pass
Q2
Q1 (Dev Territory)
Pass
Backlog Grooming
Fail

Behavior Driven Development

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