by @_md

emergent design with

I work here

I contribute here

I tweet here @_md

Marcello Duarte

it’s 2007

@padraicb

@tswicegood

a port for rspec

! = =

http://earthymoon.deviantart.com/art/Elephant-png-122633500 http://sonylisation.deviantart.com/art/Ruby-Nr-2-207831683

bowling.score.should eq(0)

in ruby everything is an object

and all objects are open

bowling.score.should eq(0)

in ruby everything is an object

and all objects are open

http://www.flickr.com/photos/owenbooth/126288240/

bowling.score.should eq(0)

in ruby everything is an object

and all objects are open

http://www.flickr.com/photos/owenbooth/126288240/

bowling.score.should eq(0)

$this->spec($bowling->getScore()) ->shouldEqual(0);

PHPSPEC EARLY SYNTAX EXAMPLE

http://www.flickr.com/photos/jamesrbowe/8403688026/

amber... red... green...

md@bossa:tests $ phpunit .PHPUnit 3.7.14 by Sebastian Bergmann.

PHP Fatal error: Class 'Customer' not found in /Users/mduarte/Documents/NoSync/Lab/phpunit/tests/CustomerTest.php on line 8

Fatal error: Class 'Customer' not found in /Users/mduarte/Documents/NoSync/Lab/phpunit/tests/CustomerTest.php on line 8

you gotta be mocking me!

public function testUpdateWithEqualTypes(){ $installer = $this->createInstallerMock(); $manager = new InstallationManager('vendor'); $manager->addInstaller($installer);

$initial = $this->createPackageMock(); $target = $this->createPackageMock(); $operation = new UpdateOperation($initial, $target, 'test');

$initial ->expects($this->once()) ->method('getType') ->will($this->returnValue('library')); $target ->expects($this->once()) ->method('getType') ->will($this->returnValue('library'));

$installer ->expects($this->once()) ->method('supports') ->with('library') ->will($this->returnValue(true));

$installer ->expects($this->once()) ->method('update') ->with($this->repository, $initial, $target);

@_md

@everzet

goals{fun to work with

goals{development toolfun to work with

goals{development toollet’s not get in the way

fun to work with

goals{enforce (mockist) TDD

development toollet’s not get in the way

fun to work with

goals{enforce (mockist) TDDdo it the PHP way

development toollet’s not get in the way

fun to work with

{ "require-dev": { "phpspec/phpspec": "2.0.*@dev" }, "config": { "bin-dir": "bin" }, "autoload": { "psr-0": { "": "src" } }}

$ bin/phpspec describe Some/Class$ bin/phpspec describe Some/Class

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ bin/phpspec describe Some/Class

$ bin/phpspec run

phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

$ bin/phpspec describe Some/Class

$ bin/phpspec run

$ editor_of_choice . phpspec generators

little demo

emergent design

design emerge iteratively driven by tests

designis...

design softwareis...

design softwareis

to describe how we’re solving a problem

calculate cost variance for a period

calculate cost variance for a period

Period

first learn design, then emergent design

“Key in making great and growable systems is to

design how its modules communicate

[and not] what their properties and behaviours should be.”

Messaging

View

poin

ts R

esea

rch

Inst

itute

Sou

rce

- Bon

nie

Mac

bird

UR

L -h

ttp://

ww

w.vp

ri.or

g

messaging

$this->person->getCar()->getEngine()->ignite();

focus on messagingmakes the code flexible

$this->person->startCar();

describing how objects interact to solve problemswhich roles, responsibilities and messages

design softwareis

big design up front

IT’S HARD TO CHANGE LATER.

WE NEED TO THINK ABOUT THINGS BEFORE DEVELOPING.

WE NEED TO MAKE SURE WE DON’T MISS ANYTHING.

THIS IS JUST THE WAY WE DO IT.

relative cost of repaircos

t

time

analysis design code test deploy rework

$

yagni

61%of the requested features are actually delivered

[Standish Group Report 06]

27%of requested features are actually used

5% to 10%are responsible for realising the benefits envisioned

design for the high priority itemsand make it easy to change later

describing how objects interact to solve problemswhich roles, responsibilities and messages

in a change-friendly way

design software in agileis

easier said than done?

test

coderefactor

use simple design rules to refactor

1. All tests run and pass2. Remove duplication3. Remove opacity4. Remove complexity

results in code

1. Testable2. Modular3. Expressive4. Simple

lack of tests breaks inner quality

1. Viscosity2. Immobility, Rigidity, Fragility3. Unreadable4. Complex

simple design is great to detect smells

simple design1. All tests run and pass2. Remove duplication3. Remove opacity4. Remove complexity

smells1. Any tests smells?2. Any DRY smells?3. Any opacity smells?4. Any complexity smells?

Test Smells

• Lack of tests

• Tests are not unitary

• Setup is too complex

• Unclear exercise

• More than one expectation in a test

• No expectation

• Too many paths

Dry Smells

• Simple duplication

• Logic duplication

• Duplication of constant

• Alternative classes with different interfaces

Opacity Smells

• Name not from domain

• Name not expressing intent

• Feature envy

• Method does more than one thing

• Method too long

• Primitive obsession

• Comments in the code

• Middle Man

Complexity Smells

• Unnecessary else

• Unnecessary if

• Unnecessary switch

• Too many arguments passed

• Inappropriate Intimacy

• Work in construction

• Static context

use design patterns to refactor

creational? behavioural? structural?

what can happen in a method?

return a value modify stateprint somethingthrow an exceptiondelegate{methods

return a value modify stateprint somethingthrow an exceptiondelegate{methods

not the final behaviour

return a value print somethingthrow an exceptiondelegate{methods

we should probably delegate that too

return a value throw an exceptiondelegate{methods

design delegation with mocks

start by defining behaviour

internally delegate to another method

Finally

• Define new role• Extract collaborators using mocks• Move behaviour definition to new collaborator test

phpspec

emergent design

simple design and smells

designing composition with mocks

Marcello Duarte

I work here

I contribute here

I tweet here @_md

Thank you !

Questions or Comments?

want to learn more? bitly.com/inviqa-bdd-training

@_md joind.in/8459