Leveling Up With Unit Testing - LonghornPHP 2022

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

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

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

✔ 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

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

😀 Bene
fi
ts of Unit Testing

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

😀 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;
}

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

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

😀 Bene
fi
ts of Unit Testing
- Continuous Integration (CI)
- Continuous Deployment (CD)

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

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

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

😀 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

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

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

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

⚙ 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>

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

⚙ PHPUnit Setup
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)

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

⚙ 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

🧑💻 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;
}

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);
}

public function testAdderThrowsExceptionWhenNotANumber()
{
$this->expectException(TypeError::class);
$adder = new Adder();
$adder->add(7, 'Can't add this');
}

public function testAdderAddsIntegers()
{
$sum = $adder->add(7, 3, 5, 5, 6, 4, 1, 9);
}
public function testAdderAddsDecimals()
{
$sum = $adder->add(1.5, 0.5);
}

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

/**
* @dataProvider dataProviderNumbers
*/
public function testAdderAddsNumbers(
float $expectedSum,
...$numbers
) {
$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];
}

• 📏 Test Coverage
- Percent of code covered by tests
- Not aiming for 100%
- No need to test language constructs

• ⛔ Self-contained
- No actual database connections
- No API calls should occur
- No external code should be called
‣ Use testing framework

• ✅ Assertions
$this->assertInstanceOf(Response::class, $response);
$this->assertEquals(200, $response->getStatusCode());
$this->assertSame(401, $responseActual->getStatusCode());
$this->assertTrue($dispatched);
$this->assertFalse($sent);

• ✅ Assertions
$this->expectException(RuntimeException::class);
$this->expectExceptionCode(403);
$this->expectExceptionMessage(‘Configuration not found.');

• Mocking
- Built-in Mock Objects
- Prophecy
- Mockery

• ⚠ Scratching the surface
- Dive deep into each
- See what you like, what works
- Leverage a mix

• Built-in Mock Objects
- Only mock certain methods, let others run as-is
- Pattern: ->method(…)->with($arg)->willReturn($value)
class RectangleTest extends TestCase

• 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)
$rectangle = new Rectangle(
$length,
$width,
$adderMock,
$multiplierMock
);

• Prophecy
- Pattern: ->shouldBeCalled()->willReturn($value)

• Prophecy
- Mock objects
- Expected method calls
- Reveal object when injecting
use ProphecyPhpUnitProphecyTrait;
class RectangleTest extends TestCase
{
use ProphecyTrait;

• Prophecy
$adderMock = $this->prophesize(Adder::class);
$multiplierMock = $this->prophesize(Multiplier::class);
$adderMock->add($length, $width)
->shouldBeCalled()
$multiplierMock->multiply(2, 10.34001)
->shouldBeCalled()
$length,
$width,
$adderMock->reveal(),
$multiplierMock->reveal()
);

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

• Mockery
- Similar style to built-in

• 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);
$length,
$width,
$adderMock,
$multiplierMock
);

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

- Missing Dependency Injection (DI)
‣ `new Thing();` in functions to be tested

- exit
- die
- print_r
- var_dump
- echo
- other outputs in-line
‣ Hint: use expectOutputString

- Time-sensitive
- sleep

- Database interactions
- Resources

- Out of class code execution
- Functional code

• ✅ Helpful Patterns
- Unit testing promotes good code patterns

- Dependency Injection
- Classes and functions focused on one thing
- Abstraction
- Interfaces
- Clean code

- 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

- DDD

- KISS
- DRY
- YAGNI

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;
}
}

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);
}

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);
}

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
);
}

💬 Discussion Items
• Convincing Teammates
• Convincing Management

• Does unit testing slow development down?

• “I don’t see the bene
fi
t of unit testing”

• Unit tests for legacy code

• Other?

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

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

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

✏ 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

Leveling Up With Unit Testing - LonghornPHP 2022

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