Writing unit testing on a project can seem like a daunting task, and earning team and leadership buy-in can be challenging. Level up your skillset as we cover PHPUnit and Prophecy setup with composer, writing meaningful tests, restructuring existing classes with dependency injection to allow for unit testing, using mock objects, and releasing code confidently with test coverage. We'll also discuss overcoming common biases, unit testing challenges, and shortcomings of unit testing.

1. Leveling Up With
Unit Testing
Mark Niebergall
https://joind.in/talk/906c6

2. 👏 Thank You!
• LonghornPHP Organizers, Sponsors
- Nucleus Security

4. https://analyze.co.za/wp-content/uploads/2018/12/441-1170x500.jpg

5. ✔ Objective
✓ Be familiar with how to setup PHPUnit
✓ Familiar with how to test existing code
✓ Know how to write unit tests using PHPUnit with
Prophecy, Mockery
✓ Convince team and management to leverage automated
testing

6. 👀 Overview
• 😀 Bene
fi
ts of Unit Testing
• ⚙ PHPUnit Setup
• 🧑💻 Writing Unit Tests
• ⌨ Testing Existing Code

7. 😀 Bene
fi
ts of Unit Testing

8. 😀 Bene
fi
ts of Unit Testing
public static function add($a, $b)
{
return $a + $b;
}

9. 😀 Bene
fi
ts of Unit Testing
public static function add($a, $b)
{
return $a + $b;
}
public function add(float ...$numbers): float
{
$return = 0;
foreach ($numbers as $value) {
$return = bcadd(
(string) $return,
(string) $value,
10
);
}
return (float) $return;
}

10. 😀 Bene
fi
ts of Unit Testing
http://www.ambysoft.com/artwork/comparingTechniques.jpg

11. 😀 Bene
fi
ts of Unit Testing
• 💻 Automated way to test code
- Regression Testing

12. 😀 Bene
fi
ts of Unit Testing
• 💻 Automated way to test code
- Continuous Integration (CI)
- Continuous Deployment (CD)

13. 😀 Bene
fi
ts of Unit Testing
• 💻 Automated way to test code
- Other ways to automatically test code
‣ Behavioral (BDD): behat, phpspec
‣ Functional
‣ Acceptance: Selenium
‣ Others?

14. 😀 Bene
fi
ts of Unit Testing
• 🪲 Decrease bugs introduced with code
- Decreased time to deployment
- Better use of QA team time

15. 😀 Bene
fi
ts of Unit Testing
• 🪲 Decrease bugs introduced with code
- High con
fi
dence in delivered code

16. 😀 Bene
fi
ts of Unit Testing
• 💯 Con
fi
dence when refactoring
- Tests covering code being refactored
- TDD
‣ Change tests
‣ Tests fail
‣ Change code
‣ Tests pass

17. ⚙ PHPUnit Setup

18. ⚙ PHPUnit Setup
• Install via composer
• Setup `phpunit.xml` for con
fi
guration (if needed)
• Run unit tests

19. ⚙ PHPUnit Setup
• phpunit/phpunit
• phpspec/prophecy-phpunit
• mockery/mockery
• fakerphp/faker

20. ⚙ PHPUnit Setup
composer require --dev phpunit/phpunit
composer require --dev phpspec/prophecy-phpunit
composer require --dev mockery/mockery
composer require --dev fakerphp/faker

21. ⚙ PHPUnit Setup
• File phpunit.xml
- PHPUnit con
fi
guration for that project
- Documentation: https://phpunit.readthedocs.io/en/9.5/
con
fi
guration.html
<?xml version="1.0" encoding="UTF-8"?>
<phpunit colors="true"
verbose="true"
bootstrap="./tests/Bootstrap.php">
<testsuite name="All Tests">
<directory>./tests</directory>
</testsuite>
</phpunit>

22. ⚙ PHPUnit Setup
• 💻 Running PHPUnit
vendor/bin/phpunit tests/

23. ⚙ PHPUnit Setup
• 💻 Running PHPUnit
vendor/bin/phpunit tests/
PHPUnit 9.5.25 by Sebastian Bergmann and contributors.
Runtime: PHP 8.1.10
Con
fi
guration: /Users/mniebergall/projects/phpunit/phpunit.xml
........... 11 / 11 (100%)
Time: 00:00.025, Memory: 8.00 MB
OK (11 tests, 15 assertions)

24. ⚙ PHPUnit Setup
• 💻 Running PHPUnit
- Within PhpStorm
- https://www.jetbrains.com/help/phpstorm/using-
phpunit-framework.html

25. ⚙ PHPUnit Setup
• 📂 Directory Structure
- PHP
fi
les in src/
‣ Ex: src/Math/Adder.php
- tests in tests/src/, ‘Test’ at end of
fi
lename
‣ Ex: tests/src/Math/AdderTest.php

26. 🧑💻 Writing Unit Tests

27. 🧑💻 Writing Unit Tests
public function add(float ...$numbers): float
{
$return = 0;
foreach ($numbers as $value) {
$return = bcadd(
(string) $return,
(string) $value,
10
);
}
return (float) $return;
}

28. 🧑💻 Writing Unit Tests
use PHPUnitFrameworkTestCase;
class AdderTest extends TestCase
{
protected Adder $adder;
public function setUp(): void
{
$this->adder = new Adder();
}
public function testAdderWithSetup()
{
$sum = $this->adder->add(3, 7);
$this->assertSame(10.0, $sum);
}

29. 🧑💻 Writing Unit Tests
public function testAdderThrowsExceptionWhenNotANumber()
{
$this->expectException(TypeError::class);
$adder = new Adder();
$adder->add(7, 'Can't add this');
}

30. 🧑💻 Writing Unit Tests
public function testAdderAddsIntegers()
{
$adder = new Adder();
$sum = $adder->add(7, 3, 5, 5, 6, 4, 1, 9);
$this->assertSame(40.0, $sum);
}
public function testAdderAddsDecimals()
{
$adder = new Adder();
$sum = $adder->add(1.5, 0.5);
$this->assertSame(2.0, $sum);
}

31. 🧑💻 Writing Unit Tests
/**
* @dataProvider dataProviderNumbers
*/
public function testAdderAddsNumbers(
float $expectedSum,
...$numbers
) {
$adder = new Adder();
$sum = $adder->add(...$numbers);
$this->assertSame($expectedSum, $sum);
}
public function dataProviderNumbers(): array
{
return [
[2, 1, 1],
[2, 1.5, 0.5],
];
}

32. 🧑💻 Writing Unit Tests
/**
* @dataProvider dataProviderNumbers
*/
public function testAdderAddsNumbers(
float $expectedSum,
...$numbers
) {
$adder = new Adder();
$sum = $adder->add(...$numbers);
$this->assertSame($expectedSum, $sum);
}
public function dataProviderNumbers(): iterable
{
yield 'integer' => [2, 1, 1];
yield 'integers with decimals' => [2, 1.5, 0.5];
}

33. 🧑💻 Writing Unit Tests
• 📏 Test Coverage
- Percent of code covered by tests
- Not aiming for 100%
- No need to test language constructs

34. 🧑💻 Writing Unit Tests
• ⛔ Self-contained
- No actual database connections
- No API calls should occur
- No external code should be called
‣ Use testing framework

35. 🧑💻 Writing Unit Tests
• ✅ Assertions
$this->assertInstanceOf(Response::class, $response);
$this->assertEquals(200, $response->getStatusCode());
$this->assertSame(401, $responseActual->getStatusCode());
$this->assertTrue($dispatched);
$this->assertFalse($sent);

36. 🧑💻 Writing Unit Tests
• ✅ Assertions
$this->expectException(RuntimeException::class);
$this->expectExceptionCode(403);
$this->expectExceptionMessage(‘Configuration not found.');

37. 🧑💻 Writing Unit Tests
• Mocking
- Built-in Mock Objects
- Prophecy
- Mockery

38. 🧑💻 Writing Unit Tests
• ⚠ Scratching the surface
- Dive deep into each
- See what you like, what works
- Leverage a mix

39. 🧑💻 Writing Unit Tests
• Built-in Mock Objects
- Only mock certain methods, let others run as-is
- Pattern: ->method(…)->with($arg)->willReturn($value)
use PHPUnitFrameworkTestCase;
class RectangleTest extends TestCase

40. 🧑💻 Writing Unit Tests
• Built-in Mock Objects
$adderMock = $this->getMockBuilder(Adder::class)
->onlyMethods(['add'])
->getMock();
$adderMock->method('add')
->with($length, $width)
->willReturn(10.34001);
$multiplierMock = $this->getMockBuilder(Multiplier::class)
->onlyMethods(['multiply'])
->getMock();
$multiplierMock->method('multiply')
->with(2, 10.34001)
->willReturn(20.68002);
$rectangle = new Rectangle(
$length,
$width,
$adderMock,
$multiplierMock
);

41. 🧑💻 Writing Unit Tests
• Prophecy
- Pattern: ->shouldBeCalled()->willReturn($value)

42. 🧑💻 Writing Unit Tests
• Prophecy
- Mock objects
- Expected method calls
- Reveal object when injecting
use PHPUnitFrameworkTestCase;
use ProphecyPhpUnitProphecyTrait;
class RectangleTest extends TestCase
{
use ProphecyTrait;

43. 🧑💻 Writing Unit Tests
• Prophecy
$adderMock = $this->prophesize(Adder::class);
$multiplierMock = $this->prophesize(Multiplier::class);
$adderMock->add($length, $width)
->shouldBeCalled()
->willReturn(10.34001);
$multiplierMock->multiply(2, 10.34001)
->shouldBeCalled()
->willReturn(20.68002);
$rectangle = new Rectangle(
$length,
$width,
$adderMock->reveal(),
$multiplierMock->reveal()
);

44. 🧑💻 Writing Unit Tests
• Prophecy
$dbMock->fetchRow(Argument::any())
->shouldBeCalled()
->willReturn([]);
$asyncBusMock
->dispatch(
Argument::type(DoSomethingCmd::class),
Argument::type('array')
)
->shouldBeCalled()
->willReturn((new Envelope(new stdClass())));

45. 🧑💻 Writing Unit Tests
• Mockery
- Similar style to built-in

46. 🧑💻 Writing Unit Tests
• Mockery
$adderMock = Mockery::mock(Adder::class);
$multiplierMock = Mockery::mock(Multiplier::class);
$adderMock->shouldReceive('add')
->with($length, $width)
->andReturn(10.34001);
$multiplierMock->shouldReceive('multiply')
->with(2, 10.34001)
->andReturn(20.68002);
$rectangle = new Rectangle(
$length,
$width,
$adderMock,
$multiplierMock
);

47. ⌨ Testing Existing Code

48. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- Long and complex functions

49. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- Missing Dependency Injection (DI)
‣ `new Thing();` in functions to be tested

50. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- exit
- die
- print_r
- var_dump
- echo
- other outputs in-line
‣ Hint: use expectOutputString

51. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- Time-sensitive
- sleep

52. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- Database interactions
- Resources

53. ⌨ Testing Existing Code
• ⚠ Problematic Patterns
- Out of class code execution
- Functional code

54. ⌨ Testing Existing Code
• ✅ Helpful Patterns
- Unit testing promotes good code patterns

55. ⌨ Testing Existing Code
• ✅ Helpful Patterns
- Dependency Injection
- Classes and functions focused on one thing
- Abstraction
- Interfaces
- Clean code

56. ⌨ Testing Existing Code
• ✅ Helpful Patterns
- Code that is SOLID
‣ Single-responsibility: every class should have only
one responsibility
‣ Open-closed: should be open for extension, but
closed for modi
fi
cation
‣ Liskov substitution: in PHP, use interface/abstract
‣ Interface segregation: Many client-speci
fi
c interfaces
are better than one general-purpose interface
‣ Dependency inversion: Depend upon abstractions,
[not] concretions

57. ⌨ Testing Existing Code
• ✅ Helpful Patterns
- DDD

58. ⌨ Testing Existing Code
• ✅ Helpful Patterns
- KISS
- DRY
- YAGNI

59. ⌨ Testing Existing Code
class ShapeService
{
public function create(string $shape): int
{
$db = new Db();
return $db->insert('shape', ['shape' => $shape]);
}
public function smsArea(Rectangle $shape, string $toNumber): bool
{
$sms = new Sms([
'api_uri' => 'https://example.com/sms',
'api_key' => 'alkdjfoasifj0392lkdsjf',
]);
$sent = $sms->send($toNumber, 'Area is ' . $shape->area());
(new Logger())
->log('Sms sent to ' . $toNumber . ': Area is ' . $shape->area());
return $sent;
}
}

60. ⌨ Testing Existing Code
class ShapeService
{
public function create(string $shape): int
{
$db = new Db();
return $db->insert('shape', ['shape' => $shape]);
}
public function smsArea(Rectangle $shape, string $toNumber): bool
{
$sms = new Sms([
'api_uri' => 'https://example.com/sms',
'api_key' => 'alkdjfoasifj0392lkdsjf',
]);
$sent = $sms->send($toNumber, 'Area is ' . $shape->area());
(new Logger())
->log('Sms sent to ' . $toNumber . ': Area is ' . $shape->area());
return $sent;
}
}

61. ⌨ Testing Existing Code
class ShapeService
{
public function __construct(
protected Db $db,
protected Sms $sms
) {}
public function create(string $shape): int
{
return $this->db->insert('shape', ['shape' => $shape]);
}
public function smsArea(ShapeInterface $shape, string $toNumber): bool
{
$area = $shape->area();
return $this->sms->send($toNumber, 'Area is ' . $area);
}

62. ⌨ Testing Existing Code
use ProphecyTrait;
protected Generator $faker;
public function setUp(): void
{
$this->faker = Factory::create();
}
public function testCreate()
{
$dbMock = $this->prophesize(Db::class);
$smsMock = $this->prophesize(Sms::class);
$shape = $this->faker->word;
$dbMock->insert('shape', ['shape' => $shape])
->shouldBeCalled()
->willReturn(1);
$shapeServiceCleanedUp = new ShapeServiceCleanedUp(
$dbMock->reveal(),
$smsMock->reveal()
);
$shapeServiceCleanedUp->create($shape);
}

63. ⌨ Testing Existing Code
public function testSmsArea()
{
$dbMock = $this->prophesize(Db::class);
$smsMock = $this->prophesize(Sms::class);
$shapeMock = $this->prophesize(ShapeInterface::class);
$area = $this->faker->randomFloat();
$shapeMock->area()
->shouldBeCalled()
->willReturn($area);
$toNumber = $this->faker->phoneNumber;
$smsMock->send($toNumber, 'Area is ' . $area)
->shouldBeCalled()
->willReturn(1);
$shapeServiceCleanedUp = new ShapeServiceCleanedUp(
$dbMock->reveal(),
$smsMock->reveal()
);
$shapeServiceCleanedUp->smsArea(
$shapeMock->reveal(),
$toNumber
);
}

64. 💬 Discussion Items
• Convincing Teammates
• Convincing Management

65. 💬 Discussion Items
• Does unit testing slow development down?

66. 💬 Discussion Items
• “I don’t see the bene
fi
t of unit testing”

67. 💬 Discussion Items
• Unit tests for legacy code

68. 💬 Discussion Items
• Other?

69. 📝 Review
• Bene
fi
ts of Unit Testing
• PHPUnit Setup
• Writing Unit Tests
• Testing Existing Code

70. Unit Testing from Setup to Deployment
• 🙋 Questions?
• https://joind.in/talk/906c6

71. Mark Niebergall @mbniebergall
• PHP since 2005
• Masters degree in MIS
• Senior Software Engineer
• Vulnerability Management project (security scans)
• Utah PHP Co-Organizer
• CSSLP, SSCP Certi
fi
ed and Exam Developer
• Endurance sports, outdoors

72. ✏ References
• https://analyze.co.za/wp-content/uploads/
2018/12/441-1170x500.jpg
• http://www.ambysoft.com/artwork/
comparingTechniques.jpg
• https://en.wikipedia.org/wiki/SOLID