Understanding bdd and tdd with lego

UnderstandingBDD & TDD with LEGO

Kev McCabe @bigmadkev !

Adapted from: Bryan Beecham @BillyGarnet Mike Bowler @mike_bowler

http://bigmadkev.com/resources


House Keeping!

▪ Please have your phones out !

▪ Please talk and have side conversations !

▪ Please Tweet, Facebook, Blog, Rave about todays sessions! – only if their good ones

Have Fun!!!!!!


BDD & TDD

▪ BDD = Behavior Driven Development !

▪ TDD = Test Driven Development


BDD & TDD

▪ They solve separate problems !

▪ They work together !

▪ TDD – Build the thing right ▪ Low level fast tests !

▪ BDD – Build the right thing ▪ Conversations & Examples


5Thanks to Nat Pryce and Steve Freeman for image


6Thanks to Nat Pryce and Steve Freeman for image


BDD

▪ Three Amigos ▪ Tester ▪ Developer ▪ Stakeholder !!!


BDD

User stories & acceptance criteria

Domain Learning

ExamplesExamplesExamplesExamplesExamples

Open QuestionsNew Stories


Having Conversations !

Is more important than capturing conversations

!

Is more important than automating conversations

www.slideshare.net/lunivore/behavior-‐driven-‐development-‐11754474 Liz Keogh @lunivore

http://www.slideshare.net/lunivore/behavior-driven-development-11754474





BDD IS NOT ABOUT THE TOOLS!

!

IT’S ABOUT THE CONVERSATIONS


Agile Stories

As a <role>, I want to <do something> so that <I get some value>.


Value Agile Stories

In order to <get some value> <role> should be able to <do something>

https://speakerdeck.com/jbrains/the-‐next-‐decade-‐of-‐agile-‐software-‐development The Next Decade (of Agile Software Development) by J. B. Rainsberger

https://speakerdeck.com/jbrains/the-next-decade-of-agile-software-development

https://speakerdeck.com/jbrains/the-next-decade-of-agile-software-development


Exercise -‐ 1

▪ Open up one LEGO packet each !

▪ Build a person and a house out of LEGO


Admire your work

▪ Take a photo. Upload to Twitter. Brag to your friends

Reference


What is the goal of TDD?

▪ It creates clean code that works ~ Ron Jefferies


TDD

▪ It is a predictable way to develop. You know when you are finished, without having to worry about a long bug trail.


TDD

▪ It gives you a chance to learn all of the lessons that the code has to teach you. If you only slap together the first thing you think of, then you never have time to think of a second, better thing.


TDD

▪ It improves the lives of the users of your software.


TDD

▪ It lets your teammates count on you, and you on them.


TDD

▪ It feels good to write it.

The MantraRed -‐ Green -‐ Refactor photo from doolwind.com


The Mantra – Red

▪Write a small test that shows the code doesn’t work


The Mantra – Green

▪Do the minimum to make the code work


The Mantra -‐ Refactor

▪ Eliminate duplication !

▪ Ensure code clarity !

▪ Is it the simplest it could be?


You won’t stay agilewithout clean code

!

You can’t have clean codewithout refactoring

!

You can’t refactor withoutgood automated tests


Exercise -‐ 2

▪ Build a person and a house with TDD


Prepare your environment

▪ Clear the area in front of you. !

▪ This is your program. !

▪ The perfect program!


First Test

▪ Does the person exist? !

▪ No?

Hurray!!! We failed the test! Celebrate! High 5s!


Minimum to pass the test

▪ Add a block. Can that be a person?


Hurray!!!

▪ The person now exists! !

▪ Not very impressive but it could represent a person. !

▪ We passed the test! We are rocking now!


Refactor

▪ Remove any duplication. In this case we’re good.


Same thing for house

▪ Is there a house?


Same thing for house

▪ You know what to do now right?


We need a new test

▪ The house is taller then the person. !

▪ Assert.IsTrue(house.height > person.height);

Hurray!!! -‐ More Failure The person is the same size so we fail this test. Well done!

Failure = Learning Opportunity

▪ If you’re not failing, you’re not learning. !

▪ If you’re not learning...


Minimum to pass the test

▪ From the audience this time. !

▪ Anyone?


Hurray!!! -‐ Success

▪ Alright, we passed the test.


Refactor

▪ Still very simple. Still nice and clean.


Software Requirements

▪ Software must do three things: ▪ It must work ▪ It must be understandable ▪ It must be updatable


We need a new test

▪ Is the house wider then the person? No? !

▪ We failed another test! Awesome! We are learning a lot about improvements that are needed to our code. !

▪ Let’s do the minimum to pass the test. !

▪ Any duplication to remove?

Exercise -‐ 3 Partners!

▪ Break into groups of two for this next exercise. !

▪ When developers do this we call it Pair Programming !

▪ Berkley photo from the web


Lego Sim Town

In order to have a town to run The Mayor requires A small town comprised of:

!A family A house A tree An animal A vehicle


We need a new test

▪ Work together and write down a new test ▪ Build minimally pass the test ▪ Repeat (Don’t worry about Refactoring for now)

▪ Here’s a few if you get stuck: ▪ Is the house at least x bricks tall? ▪ Is the tree the same size as the house? ▪ Is the animal smaller than the person?

Exercise 3 – Lego Sim Town

▪A family ▪A house

▪A tree

▪An animal ▪A vehicle

▪ Is the house at least x bricks tall? !▪ Is the tree the same size as the house? !▪ Is the animal smaller than the person?


Non-‐TDD Solution

53


Review

▪ Test-‐Driven Development / Design ▪ Refactoring ▪ Pair Programming ▪ A bit of developer speak ▪ Experience working on a software team


Four Elements of Simple Design

▪ Passes its tests !

▪ Minimizes duplication !

▪ Maximizes clarity !

▪ Has fewer elements


Closing Circle

▪ What did you learn today? !

▪ What surprised you today? !

▪ What will you do differently in the future?

Understanding bdd and tdd with lego

Software

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