BDD

Executable Requirements
Godfrey Nolan
RIIS LLC
GANG 10 Year Celebration
10/1/11

SPAM
RIIS LLC - IT Consultants and Developers since ‘98
Based in Southfield, MI
Skills
Requirements, Development, Testing
iOS/Android, Java/C#, Oracle/SQL Server
Clients
Fandango, Federal APD, Comerica, Cengage, Broadsoft, DTE, BondDesk, Proctor Financial, Blue Cross Blue Shield MI, TK, Hanson
Godfrey Nolan
godfrey@riis.com
10 years ago – Unraveling the .Net executable

Agenda

What Makes a Good Requirement?
Unique – address one thing only
Complete – no missing information
Consistent – doesn’t contradict other requirement
Traceable back to business need
Current – not obsolete
Feasible – can be implemented
Unambiguous – objective facts not subjective opinions
Mandatory – not a nice to have
Verifiable – testable

What makes a Bad Requirement?
Lengthy
Unfocused
Ambiguous
Verified Manually

Attempts at Writing Good Requirements
RIIS History – yours may be different
Company Wide Templates
Use Cases or User Stories
Requirement Reviews
Traceability Matrix tools
Requirement Metrics tools
Visualization/Simulation tools – iRise, Axure, Balsamiq
Agile Development – TDD, Scrum, Kanban
ALM, CLM tools

Use Case
Scope: ATM
Level: User Goal
1. The card gets inserted.
2. The card information gets validated.
3. The transaction information gets collected and validated.
4. The cash is issued, card returned, cash removed, account debited, screen reset.

Use Cases
1. Customer runs ATM card through the card reader.
2. ATM reads the bank id and account number.
3. ATM asks customer whether to proceed in Spanish/English.
4. Customer selects language.
5. ATM asks for PIN number and to press Enter.
6. Customer enters PIN number, presses Enter.
7. ATM presents list of activities for the Customer to perform.
8. Customer selects “withdraw cash”.
9. ATM asks customer to say how much to withdraw, in multiples of $5, and to press Enter.
10. Customer enters an amount, a multiple of $5, presses Enter.
11. ATM notifies main banking system of customer account, amount being withdrawn.
12. Main banking system accepts the withdrawal, tells ATM new balance.
13. ATM delivers the cash.
14. ATM asks whether customer would like a receipt.
15. Customer replies, yes.
16. ATM issues receipt showing new balance.
17. ATM logs the transaction.

User Story
1. User checks balance
2. User logs into the machine
3. User get "Fast Cash"
4. User makes a deposit
5. User withdraws from checking
6. User withdraws from savings

Traceability Matrix

Visualization

But inevitably…
Some or all the following happen
Scope change
Requirements confusion, opinions not facts
Developer interprets the requirement
Business stakeholder doesn’t get what they’re expecting
Completelymissed some crucial requirement
Requirements never kept up to date

But What if?
Imagine a world where developers get detailed requirements in a format and mechanism that is readable by the business facing people...
...completely devoid of ambiguity in terms of what the correct behavior is...
...and can also be used as an automated test within your team's continuous integration processes. (Tim Wingfield)

But What If? (TechTalk)

But What If?

These were the Droids you were looking for..
BDD or Behavior Driven Design
Functional Tests
Integration Tests
Acceptance Tests
ATDD or Acceptance Test Driven Design
Specification by Example
Outside In Development

Manual Testing Problem (Matt Stine)

Testing Pyramid (Lisa Crispin)

Continuous Integration

Continuous Integration
Automated Build Process
Code gets checked in
Unit tests run
Executable Requirements tests run
Code gets deployed only if everything passes
Requirements are kept up to date!

Writing Executable Requirements
Features file
Written in DSL called Gherkin
Feature description
Scenario Outline
Given/When/Then
Examples (optional)
Sample test data
Step Definitions
Setup
Regular Expressions for each Given/When/Then
Executable C# test code
Tear down

Given/When/Then

What is SpecFlow
.Nettool to write Executable Requirement in Gherkin format
Integrates with Visual Studio 2010
File->New templates for creating new feature files
Code generation Glue between Feature and Step Definition files
Gives VS debugger support
Set breakpoints on Given/When/Then lines in your .feature files
Integrates with your existing CI infrastructure
Also integrates with
NUnit
Selenium
WatiN

Good Executable Requirements
Understandable to developer
Understandable to business
Unambiguous
Automated
Run frequently

Features file
Feature description
Scenario Outline
Given/When/Then
Examples
Sample test data

Feature File

Step Definitions
Setup
Regular Expressions for each Given/When/Then
Executable C# test code
Tear down

SpecFlow Glue

Demo
SpecFlow demo

Sample Features files
Feature: Account Holder withdraws cash
In order to have access to my money
As an Account Holder
I want to withdraw cash from an ATM
Scenario: Card has been disabled
Given card is disabled
When the account holder requests money
Then the ATM should retain the card
And the ATM should say the card has been retained

Sample Features files
Feature: Serve coffee
In order to earn money
Customers should be able to
buy coffee at all times
Scenario: Buy last coffee
Given there is 1 coffee left in the machine
And I have deposited $1
When I press the coffee button
Then I should be served a coffee

Languages and Tools
Languages
C# - Specflow, Cuke4Nuke, StorEvil
Ruby – Cucumber
Java – Cuke4Duke
Also Phython, PHP etc.
Tools
Cucumber
Selenium RC
Fitnesse

Tear Down
Executable Requirements or Coding the right thing
Works well in Scrum teams
BA does feature file
Developer/tester does step definitions
Works well with VS10
Evolutionary not Revolutionary
Might be for you if you’re asking the question?
What business requirement does code coverage really provide?

Resources
URLs
http://www.specflow.org
http://dannorth.net/whats-in-a-story/
http://www.codeproject.com/KB/architecture/BddWithSpecFlow.aspx
http://cukes.info
Books

http://www.migang.org	12
http://migang.org	9
http://migang.org	9

BDD

by David Giard on Oct 02, 2011

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BDD — Presentation Transcript