Driving Design with PhpSpec

Driving Development with
PhpSpec
with Ciaran McNulty
PHPLondon November 2014

My experiences
4 Unit testing since 2004
4 Test Driven Development since 2005(ish)
4 Behaviour Driven Development since 2012

TDD vs BDD
(or are they the same?)

BDD is a second-generation,
outside-in,
pull-based, multiple-stakeholder…
1
Dan North

…multiple-scale, high-automation,
agile
methodology.
1
Dan North

BDD is the art of using
examples in conversation to
illustrate behaviour
1
Liz Keogh

Test Driven
Development
4 Before you write your code,
write a test that validates how
it should behave
4 After you have written the
code, see if it passes the test

Behaviour Driven
Development
4 Before you write your code,
describe how it should behave
using examples
4 Then, Implement the behaviour
you you described

SpecBDD with PhpSpec
Describing individual classes

History
1.0 - Inspired by RSpec
4 Pádraic Brady and Travis
Swicegood

History
2.0beta - Inspired by 1.0
4 Marcello Duarte and Konstantin Kudryashov
(Everzet)
4 Ground-up rewrite
4 No BC in specs

History
2.0 stable - The boring bits
4 Me
4 Christophe Coevoet
4 Jakub Zalas
4 Richard Miller
4 Gildas Quéméner

Installation via Composer
{
"require-dev": {
"phpspec/phpspec": "~2.1-RC1"
},
"config": {
"bin-dir": "bin"
},
"autoload": {"psr-0": {"": "src"}}
}

A requirement:
We need something that
says hello to people

Describing object behaviour
4 We describe an object using a Specification
4 A specification is made up of Examples illustrating
different scenarios
Usage:
phpspec describe [Class]

/spec/PhpLondon/HelloWorld/GreeterSpec.php
namespace specPhpLondonHelloWorld;
use PhpSpecObjectBehavior;
use ProphecyArgument;
class GreeterSpec extends ObjectBehavior
{
function it_is_initializable()
{
$this->shouldHaveType('PhpLondonHelloWorldGreeter');
}
}

Verifying object behaviour
4 Compare the real objects' behaviours with the
examples
Usage:
phpspec run

/src/PhpLondon/HelloWorld/Greeter.php
namespace PhpLondonHelloWorld;
class Greeter
{
}

An example for Greeter:
When this greets, it should
return "Hello"

{
function it_greets_by_saying_hello()
{
$this->greet()->shouldReturn('Hello');
}
}

class Greeter
{
public function greet()
{
// TODO: write logic here
}
}

Fake it till you make it
4 Do the simplest thing that works
4 Only add complexity later when more examples drive
it
phpspec run --fake

class Greeter
{
{
return 'Hello';
}
}

Describing values - Equality
$this->greet()->shouldReturn('Hello');
$this->sum(3,3)->shouldEqual(6);
$user = $this->findById(1234);
$user->shouldBe($expectedUser);
$this->numberList()
->shouldBeLike(new ArrayObject([1,2,3]));

Describing values - Type
$this->address()->shouldHaveType('EmailAddress');
$this->getTime()->shouldReturnAnInstanceOf('DateTime');
$user = $this->findById(1234);
$user->shouldBeAnInstanceOf('User');
$this->shouldImplement('Countable');

Describing values - Strings
$this->getStory()->shouldStartWith('A long time ago');
$this->getStory()->shouldEndWith('happily ever after');
$this->getSlug()->shouldMatch('/^[0-9a-z]+$/');

Describing values - Arrays
$this->getNames()->shouldContain('Tom');
$this->getNames()->shouldHaveKey(0);
$this->getNames()->shouldHaveCount(1);

Describing values - object state
// calls isAdmin()
$this->getUser()->shouldBeAdmin();
// calls hasLoggedInUser()
$this->shouldHaveLoggedInUser();

Describing custom values
function it_gets_json_with_user_details()
{
$this->getResponseData()->shouldHaveJsonKey('username');
}
public function getMatchers()
{
return [
'haveJsonKey' => function ($subject, $key) {
return array_key_exists($key, json_decode($subject));
}
];
}

Another example for Greeter:
When this greets Bob, it
should return "Hello, Bob"

Wait, what is Bob?
Bob is a Person
What is a Person?

An example for a Person:
When you ask a person
named "Alice" for their
name, they return "Alice"

/spec/PhpLondon/HelloWorld/PersonSpec.php
class PersonSpec extends ObjectBehavior
{
function it_returns_the_name_it_is_created_with()
{
$this->beConstructedWith('Alice');
$this->getName()->shouldReturn('Alice');
}
}

/src/PhpLondon/HelloWorld/Person.php
class Person
{
public function __construct($argument1)
{
}
public function getName()
{
}
}

class Person
{
private $name;
public function __construct($name)
{
$this->name = $name;
}
public function getName()
{
return $this->name;
}
}

Another example for a Person:
When a person named
"Alice" changes their name
to "Bob", when you ask
their name they return
"Bob"

{
function let()
{
}
function it_returns_the_name_it_is_created_with()
{
$this->getName()->shouldReturn('Alice');
}
}

{
function let()
{
}
// …
function it_returns_its_new_name_when_the_name_has_been_changed()
{
$this->changeNameTo('Bob');
$this->getName()->shouldReturn('Bob');
}
}

class Person
{
private $name;
// …
public function changeNameTo($argument1)
{
}
}

class Person
{
private $name;
// …
public function changeNameTo($name)
{
$this->name = $name;
}
}

Describing collaboration - Stubs
Stubs are used to describe how we interact with objects
we query
4 Maybe it is hard to get the real collaborator to
return the value we want
4 Maybe using the real collaborator is expensive

{
//…
function it_greets_people_by_name(Person $bob)
{
$bob->getName()->willReturn('Bob');
$this->greet($bob)->shouldReturn('Hello, Bob');
}
}

class Greeter
{
{
$greeting = 'Hello';
return $greeting;
}
}

class Greeter
{
public function greet(Person $person = null)
{
if ($person) {
$greeting .= ', ' . $person->getName();
}
return $greeting;
}
}

Final example for Greeter:
When it greets Bob, the
message "Hello Bob" should
be logged

What's a log?
Let's not worry yet

/src/PhpLondon/HelloWorld/Logger.php
interface Logger
{
public function log($message);
}

Describing collaboration - Mocks and
Spies
Mocks or Spies are used to describe how we interact
with objects we command
4 Maybe the real command is has side effects
4 Maybe using the real collaborator is expensive

{
function let(Person $bob)
{
}
//…
function it_greets_people_by_name(Person $bob)
{
$this->greet($bob)->shouldReturn('Hello, Bob');
}
}

{
function let(Person $bob, Logger $logger)
{
$this->beConstructedWith($logger);
}
//…
function it_logs_the_greetings(Person $bob, Logger $logger)
{
$this->greet($bob);
$logger->log('Hello, Bob')->shouldHaveBeenCalled();
}
}

class Greeter
{
public function __construct($argument1)
{
}
{
if ($person) { $greeting .= ', ' . $person->getName(); }
return $greeting;
}
}

class Greeter
{
private $logger;
public function __construct(Logger $logger)
{
$this->logger = $logger;
}
{
if ($person) { $greeting .= ', ' . $person->getName(); }
$this->logger->log($greeting);
return $greeting;
}
}

PhpSpec
4 Focuses on being descriptive
4 Makes common dev activities easier or automated
4 Drives your design

2.1 release - soon!
4 Rerun after failure
4 --fake option
4 Named constructors: User::named('Bob')
4 PSR-4 support (+ other autoloaders)
4 + lots of small improvements

Me
4 Senior Trainer at Inviqa / Sensio Labs UK / Session
Digital
4 Contributor to PhpSpec
4 @ciaranmcnulty
4 https://github.com/ciaranmcnulty/phplondon-phpspec-
talk

Driving Design with PhpSpec

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (10)

Similar to Driving Design with PhpSpec

Similar to Driving Design with PhpSpec (20)

More from CiaranMcNulty

More from CiaranMcNulty (17)

Recently uploaded

Recently uploaded (20)

Driving Design with PhpSpec