The document discusses Test Driven Development (TDD) using PhpSpec. It begins with an overview of TDD vs Behavior Driven Development (BDD). It then covers key aspects of using PhpSpec including describing object behavior with examples, verifying behavior by running tests, matchers for assertions, describing collaborations and exceptions. The rest of the document demonstrates a TDD workflow using PhpSpec to develop a greeter class and related classes like Person in a step-by-step manner.

1. TDD with PhpSpec
with Ciaran McNulty at
PHPNW 2015

2. TDD vs BDD
(or are they the same?)

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

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

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

6. 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

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

12. SpecBDD with
PhpSpec
Describing individual classes

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

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

15. Design principles
4 Optimise for descriptiveness
4 Encourage good design
4 Encourage TDD cycle
4 Do it the PHP way

16. History
2.0.0 to 2.2.0 - Steady
improvement
4 Me
4 Christophe Coevoet
4 Jakub Zalas
4 Richard Miller
4 Gildas Quéméner
4 Luis Cordova + MANY MORE

17. Installation via Composer
{
"require-dev": {
"phpspec/phpspec": "~2.0"
},
"config": {
"bin-dir": "bin"
},
"autoload": {"psr-0": {"": "src"}}
}

19. A requirement:
We need a component
that greets people

20. 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]

22. # spec/HelloWorld/GreeterSpec.php
namespace specHelloWorld;
use PhpSpecObjectBehavior;
use ProphecyArgument;
class GreeterSpec extends ObjectBehavior
{
function it_is_initializable()
{
$this->shouldHaveType('HelloWorldGreeter');
}
}

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

26. # src/HelloWorld/Greeter.php
namespace HelloWorld;
class Greeter
{
}

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

28. # spec/HelloWorld/GreeterSpec.php
class GreeterSpec extends ObjectBehavior
{
// ...
function it_greets_by_saying_hello()
{
$this->greet()->shouldReturn('Hello');
}
}

31. # src/HelloWorld/Greeter.php
class Greeter
{
public function greet()
{
// TODO: write logic here
}
}

32. So now I write some code?

33. 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

36. # src/PhpDay/HelloWorld/Greeter.php
class Greeter
{
public function greet()
{
return 'Hello';
}
}

37. Describing values
Matchers

38. Matchers
# Equality
$this->greet()->shouldReturn('Hello');
$this->sum(3,3)->shouldEqual(6);
# Type
$this->getEmail()->shouldHaveType('Email');
$this->getTime()->shouldReturnAnInstanceOf('DateTime');
# Fuzzy value matching
$this->getSlug()->shouldMatch('/^[0-9a-z]+$/');
$this->getNames()->shouldContain('Tom');

39. Object state
// isAdmin() should return true
$this->getUser()->shouldBeAdmin();
// hasLoggedInUser() should return true
$this->shouldHaveLoggedInUser();

40. Custom matchers
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));
}
];
}

41. Wildcarding
4 In most cases you should know what
arguments a method will be invoked with
4 If not, you can use wildcards
$obj->doSomething(Argument::any())->will...;
$obj->save(Argument::type(User::class))->will...;

42. Describing Exceptions

43. The shouldThrow matcher
$this->shouldThrow(InvalidArgumentException::class)
->duringSave($user);
or
$this->shouldThrow(InvalidArgumentException::class)
->during(‘save’, [$user]);

44. Construction
// new User(‘Ciaran’)
$this->beConstructedWith('Ciaran');
// User::named(‘Ciaran’)
$this->beConstructedThrough('named', ['Ciaran']);
$this->beConstructedNamed('Ciaran');
// Testing constructor exceptions
$this->shouldThrow(InvalidArgumentException::class)
->duringInstantiation();

45. Exercise
4 Install PhpSpec using composer
4 Describe a Calculator that takes two
numbers and adds them together, by
writing a few examples (using phpspec
describe)
4 Test the specificaiton and see it fail (using
phpspec run)
4 Implement the code so that the tests pass

46. The TDD Workflow

47. The Rules of
TDD
by Robert C Martin
1. Don’t write any code unless
it is to make a failing test
pass.
2. Don’t write any more of a
test than is sufficient to fail.
3. Don’t write any more code
than is sufficient to pass the
one failing test.

48. Test - Describe
the next
behaviour
4 Think about a behaviour
the object has that it
doesn’t yet
4 Describe that behaviour
in the form of a test
4 Find the simple or
degenerate cases first
4 Don’t “Go for Gold”

49. Code - Make it
pass
4 Code the most obvious
or simplest working
solution
4 Don’t overthink design
- do that later
4 The test is failing! Get
back to green ASAP

50. Refactor -
Improve the
design
4 Is there duplication?
4 What can be taken out?
4 Is the code clear and
expressive?
4 The tests are passing so
we can stop and think

51. Getting used to TDD

52. Pairing
4 Driver + Navigator roles
4 Driver controls the keyboard
4 Driver solves the immediate problems
4 Navigator checks the TDD rules are being
enforced
4 Navigator thinks about what to test next,
what future problems might come up

53. Kata
4 Short exercises to practise TDD
4 Solve an achievable problem in a fixed time
4 Throw away the code and do it again
differently
4 Focus on the process not the problem
You will probably not solve the problem on
first attempt

54. Kata
4 String Calculator
4 Roman Numbers
4 Bowling
4 Tic-Tac-Toe
4 The Command Line Argument Parser
4 Prime Factors
4 Factorial
4 String Tokeniser

55. Kata - string calculator
Design an object that takes a string expression and
calculates an integer.
4 Empty string should evaluate to zero
4 Zero as a string should evaluate to zero
4 Numeric string should evaluate to that number
4 Space separated numbers should be added together
4 Whitespace separated numbers should be added
together
4 Custom separator can be specified (e.g. ’[+]1+2+3’ -> 6)

56. Describing
Collaboration

57. Another example for Greeter:
When this greets a
person called "Bob",
it should return
"Hello, Bob"

58. # spec/HelloWorld/GreeterSpec.php
use HelloWorldPerson;
class GreeterSpec extends ObjectBehavior
{
// ...
function it_greets_a_person_by_name(Person $person)
{
$person->getName()->willReturn('Bob');
$this->greet($person)->shouldReturn('Hello, Bob');
}
}

60. The Interface
Segregation Principle:
No client should be
forced to depend on
methods it does not use
1
Robert C Martin

62. # spec/HelloWorld/GreeterSpec.php
use HelloWorldNamed;
class GreeterSpec extends ObjectBehavior
{
// ...
function it_greets_named_things_by_name(Named $named)
{
$named->getName()->willReturn('Bob');
$this->greet($named)->shouldReturn('Hello, Bob');
}
}

66. # src/HelloWorld/Named.php
namespace HelloWorld;
interface Named
{
public function getName();
}

67. # src/HelloWorld/Greeter.php
class Greeter
{
public function greet()
{
return 'Hello';
}
}

68. Finally now we write some code!

69. # src/HelloWorld/Greeter.php
class Greeter
{
public function greet(Named $named = null)
{
return 'Hello';
}
}

70. # src/HelloWorld/Greeter.php
class Greeter
{
public function greet(Named $named = null)
{
$greeting = 'Hello';
if ($named) {
$greeting .= ', ' . $named->getName();
}
return $greeting;
}
}

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

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

79. # src/HelloWorld/Person.php
class Person
{
public function __construct($argument1)
{
// TODO: write logic here
}
public function getName()
{
// TODO: write logic here
}
}

80. # src/HelloWorld/Person.php
class Person implements Named
{
private $name;
public function __construct($name)
{
$this->name = $name;
}
public function getName()
{
return $this->name;
}
}

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

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

84. # spec/HelloWorld/PersonSpec.php
class PersonSpec extends ObjectBehavior
{
function let()
{
$this->beConstructedWith('Bob');
}
function it_returns_the_name_it_is_created_with()
{
$this->getName()->shouldReturn('Bob');
}
function it_returns_its_new_name_when_it_has_been_renamed()
{
$this->changeNameTo('Alice');
$this->getName()->shouldReturn('Alice');
}
}

87. # src/HelloWorld/Person.php
class Person
{
private $name;
// …
public function changeNameTo($argument1)
{
// TODO: write logic here
}
}

88. # src/HelloWorld/Person.php
class Person
{
private $name;
// …
public function changeNameTo($name)
{
$this->name = $name;
}
}

90. Describing collaboration -
Stubs
Stubs are when we describe how we interact
with objects we query
4 willReturn()
4 Doesn't care when or how many times the
method is called

91. Describing collaboration -
Mocking and Spying
Mocks or Spies are when we describe how
we interact with objects we command
4 shouldBeCalled() or
shouldHaveBeenCalled()
4 Verifies that the method is called

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

93. # spec/HelloWorld/GreeterSpec.php
class GreeterSpec extends ObjectBehavior
{
// ...
function it_greets_named_things_by_name(Named $named)
{
$named->getName()->willReturn('Bob');
$this->greet($named)->shouldReturn('Hello, Bob');
}
}

94. # spec/HelloWorld/GreeterSpec.php
class GreeterSpec extends ObjectBehavior
{
function let(Named $named)
{
$named->getName()->willReturn('Bob');
}
// ...
function it_greets_named_things_by_name(Named $named)
{
$this->greet($named)->shouldReturn('Hello, Bob');
}
}

95. # spec/HelloWorld/GreeterSpec.php
class GreeterSpec extends ObjectBehavior
{
function let(Named $named, Logger $logger)
{
$this->beConstructedWith($logger);
$named->getName()->willReturn('Bob');
}
// ...
function it_logs_the_greetings(Named $named, Logger $logger)
{
$this->greet($named);
$logger->log('Hello, Bob')->shouldHaveBeenCalled();
}
}

100. # src/HelloWorld/Greeter.php
class Greeter
{
public function __construct($argument1)
{
// TODO: write logic here
}
public function greet(Named $named = null)
{
$greeting = 'Hello';
if ($named) { $greeting .= ', ' . $named->getName(); }
return $greeting;
}
}

101. # src/HelloWorld/Greeter.php
class Greeter
{
private $logger;
public function __construct(Logger $logger)
{
$this->logger = $logger;
}
public function greet(Named $named = null)
{
$greeting = 'Hello';
if ($named) { $greeting .= ', ' . $named->getName(); }
$this->logger->log($greeting);
return $greeting;
}
}

103. What have we built?

104. The domain model

106. Kata - String Calculator
4 The String Calculator has more than one
responsibility:
1. Splitting the string into components
2. Combining them together again by
summing
4 Do the exercise again, but this time use
more than one object to achieve the task

107. An high level test
echo $result = (new Calculator(new Splitter(), new Parser()))->evaluate('[x]1x2x3');
4 When your application becomes
composed of small self-contained
objects, you need some higher level of
testing (e.g. PHPUnit or Behat)

108. Kata - string calculator
4 Empty string should evaluate to zero
4 Zero as a string should evaluate to zero
4 Numeric string should evaluate to that number
4 Space separated numbers should be added
together
4 Whitespace separated numbers should be added
together
4 Custom separator can be specified (e.g.
’[+]1+2+3’ -> 6)

109. Thank you!
4 @ciaranmcnulty
4 Lead Maintainer of PhpSpec
4 SeniorTrainer at:
Inviqa / Sensio Labs UK / Session Digital / iKOS
4 https://joind.in/talk/view/15424
Questions?