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

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