Outside In - Behaviour Driven Development (BDD)

Behavior Driven
Development
Naresh Jain
naresh@agilefaqs.com
@nashjain
http://nareshjain.com

Copyright © 2013, AgileFAQs. All Rights Reserved.

Warmup Scenarios
Pick one scenario and in relation to your scenario,
what are the speciﬁc observable results that will tell
you that the activity has been successfully
completed?
Going out for Movie (THX sound and Digital projection)
Going out for meal (one veg.)
Going shopping ($50)
[5 Minutes]

Present back to the group your ﬁndings. [3 minutes per group]


Product
Discovery
-‐
Overview
Personas
Elevator Business Pragmatic User
Pitch Goals Personas Goals
Chartering
Scenarios Day in Life
& of each
Narratives Persona

Story Mapping Activity
Map

Interaction
UI Sketch Task Map
Design

Planning
Grouping
Reiterating Prioritization
by Themes

User Story Authoring
Acceptance User
Criteria Stories

Vision
Elevator Business
Pitch Goals

Goal
Chartering

Personas
Pragmatic User
Personas Goals

Capability
Day in Life
Scenarios &
of each
Narratives
Persona

Story Mapping
Feature
Activity Map

UI Sketch
Interaction
Design
Task Map
Story
Planning
Grouping by
Reiterating

Scenario
Prioritization
Themes

User Story Authoring
Acceptance
User Stories
Criteria

Code

User Stories
What are we really trying to build?


What is a Story?

Story is a smallest piece of functionality that add business value
Stories should follow Ron Jeffries’ 3 Cs
Card – Placeholder for conversation
Conversation – Actual discussion between dev team and user
Conﬁrmation – Acceptance criteria to determine when the story is ﬁnished


Typical Story Format

Story Title - Actor Action Context

In order to... <user goal/business justiﬁcation>
As a .. <user who requires this feature>
I need .. <do something>


Story Example

Title: Keen Reader subscribes to a blog
In order to stay up-to-date with new posts
As a keen reader of your blog
I need to subscribe to your blog


Another Story Example

Title: Social Networking Enthusiast uploads proﬁle picture
In order for my friends to see how I look and recognize me
As a Social Networking Enthusiast
I need to upload my proﬁle picture


Stories are fundamental unit of activity

Business Goals Product Backlog Release Backlog Sprint Backlog

Inception
Release planning Iteration planning

User Goals
As a ____, I want to As a ____, I want to As a ____, I want to
be able to ____ so be able to ____ so be able to ____ so
that ____ that ____ that ____
Possible automation
of the acceptance
test

I will know this is I will know this is
done when _______ done when _______
Might have an initial
estimate (perhaps for both
analysis and development),
Development team
and an expression of
breaks out the
technical and business To do this I must:
detail of work
confidence that this is real More detailed estimate, and 1) _____
needed to pass test
and achievable a specific acceptance test – 2) _____
low confidence stories might
be “spiked” or prototyped


What makes a good Story?

Stories should follow the INVEST principle:
Independent
Negotiable
Valuable
Estimateable
Small
Testable


Scenarios
Acceptance Criteria


Scenario

Is a set of conditions that the Story must meet for it to be
accepted as complete
Is typically provided by the customer or product owner.

Is not a replacement for conversation.
Is the results of the conversation

Scenarios are NOT tests


Writing Scenarios
Scenario should contain:
ACTOR
VERB – DESCRIBING A BEHAVIOR
OBSERVABLE RESULT

To accommodate pre-conditions scenarios can be expressed as
Given [Precondition]
When [Actor + Action]
Then [Observable Result]


Example
Social Networking Enthusiast uploads profile picture
Given the user has a valid facebook account and a digital picture on her computer,
When she uploads a picture in facebook,
Then her the picture should be visible to all her friends in her network.

Given an user is trying to find a friend on facebook,
When the user searches for a person using their name,
Then their profile picture should be displayed along with other details.

In order to keep facebook's reputation intact and stay out of legal hassles
As owner of facebook,
I need users to upload authentic, personal profile picture

Cucumber Style BDD
Feature: Login
In order to access secure content
As a registered user
I need to authenticate myself

Scenario: Login with valid credentials
Given I am not logged in
When I try to login with "test" and "secret"
Then I should be logged in

Scenario: Login with invalid credentials
Given I am not logged in
When I try to login with "test" and "wrongpassword"
Then I should not be logged in
And I should be shown error message "Invalid username or password"

Step Definition
Given /Î am not logged in$/ do
browser.navigate_to("http://your_url.com")
end

When /Î try to login with "([^"]*)" and "([^"]*)"$/ do |username, password|
browser.textbox("user").value = username
browser.password("password").value = password
browser.submit("Login").click
end

Then /Î should be logged in$/ do Then /Î should not be logged in$/ do
if !browser.button("Logout").exists? if !browser.submit("Login").exists?
raise "Not logged in" raise "Logged in"
end end
end end

Then /Î should be shown error message "([^"]*)"$/ do |msg|
value = browser.div("errorMessage").text
if value != msg
raise "Incorrect message: #{value}"
end
end

Acceptance Criteria & Tests: Deﬁnition
Acceptance Tests

Acceptance Criteria
+ Examples (data + scenarios)

Acceptance Tests

Scenarios
=
Executable Tests


Tasks
Team members further break down each story into tasks that need
to be completed to meet the acceptance criteria for the story.

To accomplish this story:
we start off with a simple upload and image display
restrict user to only upload certain image types (gif, jpg and png)
ﬁgure out where to store the image. (performant and fault-tolerant)
scale down (size, resolution, etc.) of the image
and so on...


Demo


BDD


Key Questions

Business Facing

Are we building the right product?

Are we building the product right?

Technology/Implementation Facing


Brian Marick’s Test Categorization

Business Facing
Supports Programming

Critique product


It Helps to Think of Tests this way...

Business Facing

Acceptance Testing Exploratory Testing
Drives Development

Critique product
Low-ﬁ prototypes UI and Usability Testing

Performance Testing
Unit Testing
System Tests


Inverting the Testing Pyramid
Typical testing strategies lead to an inverted testing pyramid...

Manual Checking

End-to-End
GUI Tests 80-90%

Integration
5-15%
Tests

Unit
Tests 1-5%

Inverting the Testing Pyramid
GUI 1%
Tests Performance
Tests
End to End 4% Security
Flow Tests Tests
One Layer Below GUI

Workﬂow Tests 6%

Integration Test 9%

Biz Logic Acceptance Tests 10%

Unit Tests 70%

This is the need of the hours...

Test Driven Development

Add a Test

Pass
Run the Test

Fail
TDD Rhythm - Test, Code, Refactor Make a little
change

Fail
Run the Test
Pass
Refactor


Behavior Driven Development
Iteration

Automated
Acceptance Tests P
Scenario E
R
F
O
R
Story Automated M
Unit Test E
T
Automated UI N
E
C
Tests S
E
T
S

Automated
Acceptance Tests

Exploratory Scenario
Testing


Beneﬁts of BDD


Why?


Better Commitment and Buy-in
Focus on Business Value


Ubiquitous Domain Language


Right focus


Evolutionary Design


Breaking the Knowledge Silos in Distributed Team


Greater ROI


Predictability & Conﬁdence


Thank you
Naresh Jain
naresh@agilefaqs.com


Outside In - Behaviour Driven Development (BDD)

Outside In - Behaviour Driven Development (BDD)

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