Using Behavior Driven Development and Feature Injection to ...goodrequirements.com/downloads/Using-BDD-and... · Fundamentals of BDD ! Formal definition ! What is BDD? ! How to use

Using Behavior Driven Development

and Feature Injection to Build Better Software

Jeffrey Davidson @JeffreyGoodReq goodrequirements.com BBCCon2011:baf November 3, 2011

© Jeffrey Davidson, 2011

BDD Fundamentals

!  I can teach you this in less than 1 minute . . .

!  Are you ready?

!  Seriously. Do you have your pencil ready?

!  Can someone time me?


60 minutes in less than 60 seconds

!  Without using any technical language…

!  Describe who you are and what your condition is

!  And what you do !  And how the system responds


– – Given You & You

r condition

What you do

What you see

Simple Structure

When Then


Given – When – Then

You now know enough to succeed.

Go! Enjoy another session.


Today’s Agenda…

!   Fundamentals of BDD !   Formal definition !   What is BDD? !   How to use BDD !   Why being less specific is important !   Benefits !   Why you should care !   Why BDD isn’t testing !   More Fundamentals (Feature Injection) !   How to use Feature Injection !   How this directly relates to BDD


Not Today’s Agenda

!  Discuss BDD Tools !  Give automation advice !  Share code quality practices


What is BDD?

“BDD is a second-generation, outside-in, pull-based, multiple-stakeholder, multiple-scale, high-automation, agile methodology. It describes a cycle of interactions with well-defined outputs, resulting in the delivery of working, tested software

that matters.”

Dan North @ Agile Specifications, 2009


What is BDD?

!  Fine grained, focused bits of behavior

!  Told in a story format

No, really, what is it?


Stories & Story Format

!  When you take a few minutes to talk to your co-workers, your boss, your spouse, and your family . . .

. . . do you give facts or context?



!  I dream of . . . adventure, challenge, success



!  Have you ever dreamed of . . . facts?

Yuck!


Stories

!  We use stories to communicate.


Do you mean User Stories?

!  “As a . . . , I want . . . , So . . . .”


User Stories are Statements

!  User Stories do not give all the preconditions !  Or all the actors actions !  Or all the system responses

!  Promise of a future conversation


Two Steps

!  Start with business goals !  In Agile development, this is a

User Statement Story

!  Build Scenarios


– – Given You & You

r condition

What you do

What you see

Simple Structure

When Then


Simple Structure

!  Given [CONTEXT]

!  When [EVENT OCCURS]

!  Then [OUTCOME]


Given

OLD !  ?

NEW !  Given I am . . .

<<Who & Where & What has already happened & etc.>>

State your action in natural language


When

OLD !  ?

NEW !  When I <<perform

some action>>



NEW !  Then I see …

Then

OLD !  The system shall …

This is how you

observe the system’s

response


– OR – WRITE LIKE A

HUMAN


Be Like Aldi

!  Generic behavior

!  Don’t include design.

Imagine performing the same actions on a telephone interface!


Simple Structure

!  Given [CONTEXT]

!  When [EVENT OCCURS]

!  Then [OUTCOME]


I want to withdraw $ from ATM (An example)

Scenario #1: Account has sufficient funds

!  Given the account balance is 100 !   and the card is valid !   and the machine contains enough money !  When the account holder requests 20 !  Then the ATM should dispense 20 !   and the account balance should be 80 !   and the card should be returned


What is it?

!  It’s a bunch of tiny stories, using a particular grammatical structure.

!  It’s finding places of misunderstanding, and filling it with understanding.

!  It’s a conversation, captured.


Why?


Simple Made Easy

!  “We can only hope to make reliable those things that we can understand.

!  We can only consider a few things at a time. !  Intertwined things must be considered

together. !  Complexity undermines understanding.”

Rich Hickey @ StrangeLoop 2011


Built right or Right product?

Gojko Adzic in Specification by Example, 2011


Benefits

To build the right product effectively, software dev practices need:



Benefits

To build the right product effectively, software dev practices need: !  Assurance all stakeholders & delivery

team members understand what needs to be delivered in the same way.



Benefits

To build the right product effectively, software dev practices need: !  Precise specifications so delivery teams

avoid wasteful rework caused by ambiguities and functional gaps.



Benefits

To build the right product effectively, software dev practices need: !  An objective means to measure when a

piece of work is complete.



Benefits

To build the right product effectively, software dev practices need: !  Documentation to facilitate change, in

terms of both software features & team structure.



Who Benefits?

!  Everyone!

!  Seriously, it helps everyone. •  Business •  Users •  Testers •  Developers •  Analysts


Blah, Blah, Blah – Why should I care?

!  Ferries & Bridges


Isn’t this just testing?

!  Seems like TDD to me

!  “Umm, what’s TDD?”

!  If you’re doing TDD, then BDD is a great next step.


Acceptance Test Criteria

!  Tests code or functionality

!  Presumes the test is right

!  Who really cares about the functionality? •  It’s an IT term! •  Users care about the behavior


BDD > TDD

!  Presumes we don’t know everything

!  So we ask about scenarios

!  It’s about behavior •  You can only learn about behavior from

conversation

!  Behavior leads to design

“Can you give me an example?”


Is it like testing?

!  Sort of…

!  Specifications are written in such a precise way we can execute them


Testing Tools

! JBehave (java) ! RSpec, Cucumber (ruby) !  Lettuce (python) ! Nbehave & Nspec (.NET) !  FIT & FitNess (multiple) !  Etc.

There are lots of tools to use


It’s not about tools

“These tools are intended for use by programmers to guide coding, but they can also be used to express business facing tests that drive development, involving customers more closely in the process.”

Lisa Crispin in Agile Testing, 2009


Downsides

!  May not help velocity

!  New

!  Tools (and all that jazz) may cause clutter, slow-down, new learning, other stuff


Wait a minute!

!  What happened to Feature Injection?


Build Software That Matters

!  Start with a business goal

Hint: Businesses want to increase, conserve, or protect $.


Feature Injection

!  The value of an IT system is in it’s outputs / outcomes

!  Model based on desired results

!  Follow Information Smells to identify that may be missing from your model


Value is what matters

!  If you want to add value . . .

!  . . . don’t argue about features

!  . . . ask about why


Think like an investor

!  Every project is an investment.

!  Picture a Business Investor

!  Why does your Business Investor want to do this project?


Why invest?

!  Avoid penalty !  Keep up with the market – competitor !  Always done this way !  Want to spend budget to keep it safe !  Bad PR via social media !  Et cetera

Whatever the reason, know the reason


Information Smells

1.  Item on output, that are not on the model 2.  Item on model, that are not on the output 3.  Two pieces of information in one place 4.  No relationship 5.  One to one relationship. Are they the same thing? 6.  Many to many ( missing information ) 7.  Undefined functions ( missing information )

Chris Matts, to be published soon


It’s the same thing

!  Discussing the Information Smells •  Not about do we need this data? •  Conversation about what business needs

!  Changes the dynamic

!  Transforms from push to pull


BDD: Recap

!  Start with a goal or User Story

!  Build scenarios

!  Automate the testing

!  Write the code

!  Have a Coca-Cola and smile


Feature Injection: Recap

!  Find the value

!  Model the output

!  Follow the Information Smells

!  Have another Coke!


Questions

!  If you waited until now to ask your questions, you missed the best chance for us to have a conversation.

!  But you should ask anyway…


Experts

!  Dan North @tastapod dannorth.net !  Chris Matts @PapaChrisMatts theitriskmanager.wordpress.com !  Liz Keogh @lunivore lunivore.com ! Gojko Adzic @gojkoadzic

gojko.net


Resources

http://www.lulu.com/product/ebook/real-options-at-agile-2009/17416200

This is a really

cool comic. You

should read it.







Using Behavior Driven Development and Feature Injection to ...goodrequirements.com/downloads/Using-BDD-and... · Fundamentals of BDD ! Formal definition ! What is BDD? ! How to use

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