1. @asgrim
Crafting Quality PHP
Applications: an overview
James Titcumb
PHPSW 2018 meetup

2. $ whoami
James Titcumb
www.jamestitcumb.com
www.roave.com
@asgrim

3. @asgrim

4. @asgrim
What is “quality”?

5. @asgrim
photo: Rob Allen https://flic.kr/p/qmGpsq

6. @asgrim
photo: https://goo.gl/QHWXQL

7. @asgrim
photo: Rob Allen https://flic.kr/p/ecFbH8

8. @asgrim
Quality.

9. @asgrim
"The best code is no code at all”
-- Jeff Atwood
source: https://blog.codinghorror.com/the-best-code-is-no-code-at-all/

10. @asgrim
Trade-offs.

11. @asgrim
Prototyping & short-lived apps/sites

12. @asgrim
Products
Long-lived projects. Open source software.

13. @asgrim
What is quality in applications?

14. @asgrim
What about time/cost…?

15. @asgrim
“A freelancer at $25 an hour for 100 hours still
costs more than a freelancer at $150 an hour that
takes 10 hours to do the same task”
-- Brandon Savage
source: http://www.brandonsavage.net/earning-more-money-as-a-php-freelancer/

16. @asgrim
Get an expert in.

17. @asgrim
Complexity

18. @asgrim
Processes

19. @asgrim
This talk...
● Planning
● Development
● Testing
● Continuous integration
● Code reviews
● Deployments

20. @asgrim
Planning

21. @asgrim
Planning is communication

22. @asgrim
Use business terminology

23. @asgrim
Explore and discover

24. @asgrim
Build a model of the business

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26. @asgrim

27. @asgrim
The model must be fluid.

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Development

29. @asgrim
Care about code

30. @asgrim
“There are only two hard things in Computer
Science: cache invalidation and naming things.”
-- Phil Karlton
source: https://martinfowler.com/bliki/TwoHardThings.html

31. @asgrim
SimpleBeanFactoryAwareAspectInstanceFactory

32. @asgrim
Loader

33. @asgrim
Describe intent

34. @asgrim
“Give awkward names to awkward concepts”
-- Eric Evans
source: https://skillsmatter.com/conferences/8231-ddd-exchange-2017

35. @asgrim
SOLID

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KISS

37. @asgrim
Object Calisthenics

38. @asgrim
Avoid early abstraction

39. @asgrim
“Code for your use-case,
not for your re-use-case”
-- Marco Pivetta
source: https://ocramius.github.io/extremely-defensive-php/#/39

40. @asgrim
Care about your API

41. @asgrim
A public method is like a child:
once you've written it,
you are going to maintain it
for the rest of its life!
-- Stefan Priebsch

42. @asgrim
Strict type declarations.
Use declare(strict_types=1); by default

43. @asgrim
Immutable value objects
declare(strict_types=1);
use AssertAssertion; // beberlei/assert library !
final class PostalCode
{
private const VALIDATION_EXPRESSION = '(GIR 0AA)|((([A-Z-[QVX]][0-9][0-...
/** @var string */
private $value;
public function __construct(string $value) {
$this->assertValidPostalCode($value);
$this->value = $value;
}
private function assertValidPostalCode(string $value) : string {
Assertion::regex($value, self::VALIDATION_EXPRESSION);
}
public function __toString() : string {
return $this->value;
}
}

44. @asgrim
Value objects are valid!
declare(strict_types=1);
final class Thing {
public function assignPostalCode(PostalCode $postalCode) : void
{
// ... we can trust $postalCode is a valid postal code
}
}
// 12345 is not valid - EXCEPTION!
$myThing->assignPostalCode(new PostalCode('12345'));
// assignPostalCode is happy
$myThing->assignPostalCode(new PostalCode('PO1 1AA'));
// With STRICT types, this will also FAIL
$myThing->assignPostalCode(new PostalCode(12345));

45. @asgrim
Testing

46. @asgrim
Testing is NOT a separate line item

47. @asgrim
Testing should be an assumption

48. @asgrim
You’re already testing.

49. @asgrim
Still need convincing?

50. @asgrim
How?

51. @asgrim
Reduce complexity

52. @asgrim
Reduce complexity
public function process(Stuff a, string b, int c) : MoreStuff
{
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code
// lots of complicated code

53. @asgrim
Reduce complexity
public function meaningfulThing(Stuff a, string b, int c) : More
{
// call nicer, meaningful methods below
}
private function throwStuffIntoFire(Stuff a) : Fire
{
// smaller, meaningful chunk of code
}
private function combineStringWithFire(Fire a, string b) : string
{
// simple, lovely code!
}
private function postFlowersToSpain(int c) : void

54. @asgrim
More complexity = more tests

55. @asgrim
Test coverage

56. @asgrim
Line coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);

57. @asgrim
Line coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);

58. @asgrim
Branch coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);

59. @asgrim
Branch coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);

60. @asgrim
Branch coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);
foo(false, false); // NEW TEST!!!

61. @asgrim
Branch coverage
<?php
function foo(bool $a, bool $b) {
if ($a) {
echo "A";
}
if ($b) {
echo "B";
}
}
// generate coverage using calls:
foo(true, false);
foo(false, true);
foo(false, false); // NEW TEST!!!
foo(true, true); // NEW TEST!!!

62. @asgrim
Prevent coverage leaking

63. @asgrim
Prevent coverage leaking
<?php
namespace Foo;
/**
* @covers FooBar
*/
final class BarTest extends TestCase
{
// write some tests!
}

64. @asgrim
Are the tests testing?

65. @asgrim
Example of a test not testing…
public function testPurchaseTickets()
{
$event = Event::create(uniq('event', true)
$customer = Customer::create(uniq('name', true));
$shop->purchaseTicket(1, $event, [$customer]);
}
@asgrim

66. @asgrim
Assert you’re asserting
public function testPurchaseTickets()
{
$event = Event::create(uniq('event', true)
$customer = Customer::create(uniq('name', true));
$receipt = $shop->purchaseTicket(1, $event, [$customer]);
self::assertSame($event, $receipt->event());
$customersInReceipt = $receipt->customers();
self::assertCount(1, $customersInReceipt);
self::assertContains($customer, $customersInReceipt);
}
@asgrim

67. @asgrim
Test the tests are testing!

68. @asgrim
Mutation testing
function add(int $a, int $b) : int {
return $a + $b;
}
function testAdd() {
$result = add(2, 3);
// self::assertSame(5, $result);
}

69. @asgrim
Mutation testing
function add(int $a, int $b) : int {
return $a - $b;
}
function testAdd() {
$result = add(2, 3);
// self::assertSame(5, $result);
}

70. @asgrim
Mutation testing
function add(int $a, int $b) : int {
return $a - $b;
}
function testAdd() {
$result = add(2, 3);
self::assertSame(5, $result);
// /// test will now fail with mutation
}

71. @asgrim
What about other tests?

72. @asgrim
Integration tests

73. @asgrim
Behaviour tests

74. @asgrim
BAD! Do not do this.
Feature: Ability to print my boarding pass
Scenario: A checked in passenger can print their boarding pass
Given I have a flight booked
And I have checked in
When I visit the home page
And I click the ".manage-booking" button
And I enter "CJM23L" in the ".bref-ipt-fld" field
And I click the "Find Booking" button
Then I should see the ".booking-ref.print" button
When I click the ".booking-ref.print" button
Then I should see the print dialogue

75. @asgrim
Better Behaviour test
Feature: Ability to print my boarding pass
Policies:
- Boarding passes are only available when already checked in
- If customer cannot print boarding pass, they can collect at
The airport
- more business rules etc...
Scenario: A checked in passenger can print their boarding pass
Given I have a flight booked for LHR-OTP on 24th May
And I have previously checked in for the flight
When I display my booking reference "CJM23L"
Then I should be able to print my boarding pass
And the boarding pass should display flight details correctly

76. @asgrim
Why is this important?

77. @asgrim
Automate these tests

78. @asgrim
Automated tests
Application (and UI, API, etc.)
Domain / Business Logic
Infrastructure (DBAL, APIs, etc.)

79. @asgrim
Automated tests
Application (and UI, API, etc.)
Domain / Business Logic
Infrastructure (DBAL, APIs, etc.)

80. @asgrim
Testing at domain layer
Application (UI, API, etc.)
Domain / Business Logic
Infrastructure (DB, APIs, etc.)
// Testing via the UI
public function iDisplayMyBookingReference(string $reference)
{
$page = $this->getSession()->getPage();
$page->click(".manage-booking");
$page->findField(".bref-ipt-fld")->setValue($reference);
$page->click("Find Booking");
}
// Using the domain layer directly in tests
public function iDisplayMyBookingReference(string $reference)
{
$this->booking = $this->retrieveBooking($reference);
}

81. @asgrim
Some UI testing is okay!!!
Feature: Ability to print my boarding pass
Policies:
- Boarding passes are only available when already checked in
- If customer cannot print boarding pass, they can collect at
The airport
- more business rules etc...
@ui
Scenario: A checked in passenger can print their boarding pass
Given I have a flight booked for LHR-OTP on 24th May
And I have previously checked in for the flight
When I display my booking reference "CJM23L"
Then I should be able to print my boarding pass
And the boarding pass should display flight details correctly

82. @asgrim
Automate all the things!

83. @asgrim
Continuous Integration

84. @asgrim
Tests cost money to run
(manually)

85. @asgrim
Travis-CI.com

86. @asgrim
Jenkins

87. @asgrim
What to automate?

88. @asgrim
The goal?

89. @asgrim
Code reviews

90. @asgrim
What to look for in code review?

91. @asgrim
What to look for in code review?
Code style.

92. @asgrim
What to look for in code review?
Small, atomic changes.

93. @asgrim
What to look for in code review?
Composer versions.

94. @asgrim
What to look for in code review?
Structure & good practices.

95. @asgrim
What to look for in code review?
Tests.

96. @asgrim
What to look for in code review?
Documentation.

97. @asgrim
What to look for in code review?
Security.

98. @asgrim
What to look for in code review?
Insight.

99. @asgrim
It takes practice.

100. @asgrim
Deployments

101. @asgrim
Automate deployments!

102. @asgrim
One-click deployments

103. @asgrim
“Move fast and break things”
-- a stupid Facebook mantra

104. @asgrim
“Move fast and break things with stable infra”
-- Facebook mantra since 2014

105. @asgrim
Continuous Delivery & Deployment

106. @asgrim
Better quality

107. @asgrim
Better quality = Higher confidence

108. @asgrim
Better quality = Higher confidence = Happy customers

109. Any questions?
https://joind.in/talk/96cee
James Titcumb
@asgrim