Legacy Code - Longhorn PHP 2022

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@maccath | Katy Ereira | #LonghornPHP Legacy Code. testing & safe refactoring

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@maccath | Katy Ereira | #LonghornPHP What is legacy code? ● Code that wasn’t written by you, just now ● Code resulting from incorrect assumptions ● Code built using unsupported technology ● Code that isn’t tested

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@maccath | Katy Ereira | #LonghornPHP What is refactoring? ● Updating existing code without changing the application logic ● Improving code structure ● Usually done in small, incremental steps

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@maccath | Katy Ereira | #LonghornPHP Why would I refactor? ● Improve other developer’s understanding ● Increase the application’s performance ● Introduce new technology ● Accommodate changes

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@maccath | Katy Ereira | #LonghornPHP What is unit testing? ● Veriﬁcation that each individual ‘unit’ of an application works as intended ● Units are the component parts of your application ● Generally, each behaviour is a unit; likely to be contained within a function ● Unit testing is not a substitute for other types of testing

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@maccath | Katy Ereira | #LonghornPHP Why would I unit test? ● Aid in the documentation of the system ● To prevent regressions when changing code ● To test integration with new technology ● For validation of product requirements

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@maccath | Katy Ereira | #LonghornPHP Paradox: can’t refactor untested code, but can’t test the code until it’s refactored.

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@maccath | Katy Ereira | #LonghornPHP A solution 1. Rewrite the entire codebase 2. … 3. Proﬁt! 1. Rewrite the entire codebase 2. … 3. Proﬁt!

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@maccath | Katy Ereira | #LonghornPHP A better solution 1. Perform just enough refactoring to make the code testable 2. Test the code 3. Lather, rinse, repeat. 4. Proﬁt!

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@maccath | Katy Ereira | #LonghornPHP Assumptions: you’re developing with PHP and you have access to a terminal with Composer.

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@maccath | Katy Ereira | #LonghornPHP “ PHPUnit is a programmer-oriented testing framework for PHP. It is an instance of the xUnit architecture for unit testing frameworks. PHPUnit Reference: https:/ /phpunit.de/

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@maccath | Katy Ereira | #ScotPHP19 I’m still on PHP version 5.6 / 7.0 / 7.1 ! PHPUnit Version PHP Version Requirement Supported Until 10 8.1 Future release 9 >= 7.3 February 2, 2024 8 >= 7.2 February 3, 2023 7 7.1, 7.2, 7.3 February 7, 2020 6 7.0, 7.1, 7.2 February 8, 2019 5 5.6, 7.0, 7.1 February 2, 2018

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@maccath | Katy Ereira | #ScotPHP19 Install via Composer: PHPUnit - installation $ composer require --dev phpunit/phpunit ^|version| $ ./vendor/bin/phpunit --version PHPUnit x.y.z by Sebastian Bergmann and contributors.

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@maccath | Katy Ereira | #ScotPHP19 Anatomy of a unit test tests/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function testSomeFunction() { $result = someFunction(); // Should return true $this->assertTrue($result); } }

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@maccath | Katy Ereira | #ScotPHP19 Run your tests: Running the tests $ ./vendor/bin/phpunit tests PHPUnit 7.5.8 by Sebastian Bergmann and contributors. . 1 / 1 (100%) Time: 64 ms, Memory: 4.00 MB OK (1 test, 1 assertion)

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@maccath | Katy Ereira | #LonghornPHP Mocking ● Create test doubles ● Verify the behaviour of your code ● Isolate the system under test

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@maccath | Katy Ereira | #LonghornPHP Mocking - Caution! DO: ● Mock dependencies, when needed. ● Be aware of tautological testing. DON’T: ● Mock everything. ● Mock the system under test.

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@maccath | Katy Ereira | #LonghornPHP “ Mockery Mockery is a simple yet ﬂexible PHP mock object framework for use in unit testing with PHPUnit, PHPSpec or any other testing framework. Reference: https:/ /github.com/mockery/mockery

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@maccath | Katy Ereira | #LonghornPHP Install via Composer: $ composer require --dev mockery/mockery Mockery - Installation

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@maccath | Katy Ereira | #LonghornPHP Mockery - Usage tests/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function setUp(): void { $mockObject = Mockery::mock(Object::class); $mockObject->shouldReceive('method') // Expect that ‘method’ ->once() // should be called once ->andReturn(true); // and return true } }

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@maccath | Katy Ereira | #LonghornPHP Mockery - Usage tests/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function tearDown(): void { Mockery::close(); // Always close after running tests! } }

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@maccath | Katy Ereira | #LonghornPHP Disclaimer: the following examples are deliberately simple.

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #1 Interfering Output

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP hillsAreAlive.php function yodel($tune = null) { if ($tune) { echo $tune; // The yodel is echoed back } else { echo 'Odl lay ee'; // A yodel begins } } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP A method that echoes tests/YodelTest.php class PrintedOutputTest extends PHPUnit\Framework\TestCase { public function testNewYodel() { yodel(); // Should echo ‘Odl lay ee’ } public function testEchoedYodel() { yodel('Lay hee hoo'); // Should echo ‘Lay hee hoo’ } }

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@maccath | Katy Ereira | #LonghornPHP Run your tests: A method that echoes $ ./vendor/bin/phpunit tests PHPUnit 7.5.8 by Sebastian Bergmann and contributors. ROdl lay eeR 2 / 2 (100%)Lay hee hoo Time: 60 ms, Memory: 4.00 MB There were 2 risky tests

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@maccath | Katy Ereira | #LonghornPHP ● Prevent output being echoed to the test runner ● Capture the output that would otherwise be echoed ● Perform assertions on the captured output A method that echoes

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@maccath | Katy Ereira | #LonghornPHP tests/YodelTest.php public function testNewYodel() { ob_start(); // Start capturing output. yodel(); } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP tests/YodelTest.php public function testNewYodel() { ob_start(); yodel(); ob_end_clean(); // Finish capturing output. } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP tests/YodelTest.php public function testNewYodel() { ob_start(); yodel(); $output = ob_get_contents(); // Get the output. ob_end_clean(); } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP tests/YodelTest.php public function testNewYodel() { ob_start(); yodel(); $output = ob_get_contents(); ob_end_clean(); $this->assertEquals('Odl lay ee', $output); // Success! } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP tests/YodelTest.php public function testEchoedYodel() { ob_start(); yodel('Lay hee hoo'); $output = ob_get_contents(); ob_end_clean(); $this->assertEquals('Lay hee hoo', $output); // Success! } A method that echoes

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #2 Static method calls

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP Vegeta.php function getPowerLevel() { $result = Goku::powerLevel(); // Goku’s power level is static. return $result > 9000 ? "It’s over 9000!" : "Suppressed."; } A static method call

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@maccath | Katy Ereira | #LonghornPHP tests/PowerLevelTest.php class PowerLevelTest extends PHPUnit\Framework\TestCase { public function testUnder9000() { $result = getPowerLevel(); } public function testOver9000() { $result = getPowerLevel(); } } A static method call

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@maccath | Katy Ereira | #LonghornPHP Goku.php class Goku { static function powerLevel() { return 5000; // Always returns 5000. } } A static method call

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@maccath | Katy Ereira | #LonghornPHP tests/PowerLevelTest.php public function testUnder9000() { $result = getPowerLevel(); $this->assertEquals('Suppressed.', $result); // Success! } A static method call

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@maccath | Katy Ereira | #LonghornPHP tests/PowerLevelTest.php public function testOver9000() { $result = getPowerLevel(); $this->assertEquals('It’s over 9000!', $result); // Failure. } A static method call

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@maccath | Katy Ereira | #LonghornPHP A static method call ● Create a new ‘mock’ of Goku, using a Mockery alias. ● Set the return value of Goku::powerLevel to be 9001. ● Run tests in separate processes.

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@maccath | Katy Ereira | #LonghornPHP A static method call tests/PowerLevelTest.php public function testOver9000() { $superSaiyanGoku = Mockery::mock('alias:Goku'); // Mock Goku $result = getPowerLevel(); $this->assertEquals('It’s over 9000!', $result); // Failure. }

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@maccath | Katy Ereira | #LonghornPHP A static method call tests/PowerLevelTest.php public function testOver9000() { $superSaiyanGoku = Mockery::mock('alias:Goku') ->shouldReceive('powerLevel') // Set Goku’s power level ->andReturn(9001); // to over 9000. . $result = getPowerLevel(); $this->assertEquals('It’s over 9000!', $result); // Failure. }

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@maccath | Katy Ereira | #LonghornPHP A static method call tests/PowerLevelTest.php public function testOver9000() { // Goku is super saiyan! Mockery::mock('alias:Goku') ->shouldReceive('powerLevel') ->andReturn(9001); . $result = getPowerLevel(); $this->assertEquals('It’s over 9000!', $result); // Success! }

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP A static method call tests/PowerLevelTest.php /** * @runTestsInSeparateProcesses * @preserveGlobalState disabled */ class PowerLevelTest extends PHPUnit\Framework\TestCase { // ... }

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #3 Hard-coded dependencies

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP PessimistOrOptimist.php function getOutlook() { $weather = new WeatherForecast(); // A hard-coded dependency. $outlook = $weather->isSunny() ? "full" : "empty"; return "The glass is half $outlook."; } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP WeatherForecast.php class WeatherForecast { static function isSunny() { return (bool) rand(0, 1); // Returns random true/false. } } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php class OutlookTest extends PHPUnit\Framework\TestCase { public function testHalfFull() { $result = getOutlook(); } public function testHalfEmpty() { $result = getOutlook(); } } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfEmpty() { $result = getOutlook(); $this->assertEquals('The glass is half empty.', $result); } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP Testing: hard-coded dependencies ● Mock the WeatherForecast, using a Mockery override. ● Set the return value of WeatherForecast::isSunny to be true or false. ● Perform assertions based on mocked return values. ● Run tests in separate processes.

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock('overload:WeatherForecast'); // Overload $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock('overload:WeatherForecast') ->shouldReceive('isSunny'); // Set expectation $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock('overload:WeatherForecast') ->shouldReceive('isSunny') ->andReturn(true); // Force return value true $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock('overload:WeatherForecast') ->shouldReceive('isSunny') ->andReturn(true); // Force return value true $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfEmpty() { $mockForecast = Mockery::mock('overload:WeatherForecast') ->shouldReceive('isSunny') ->andReturn(false); // Force return value false $result = getOutlook(); $this->assertEquals('The glass is half empty.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php /** * @runTestsInSeparateProcesses * @preserveGlobalState disabled */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP ● Refactor the code to use an injected dependency. ● Mock the dependency. ● Inject the mocked dependency. ● Remove @runTestsInSeparateProcesses annotation. Refactoring: hard-coded dependencies

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@maccath | Katy Ereira | #LonghornPHP myLegacyCode.php function getOutlook() { $weather = new WeatherForecast(); $outlook = $weather->isSunny() ? "full" : "empty"; return "The glass is half $outlook."; } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP myLegacyCode.php function getOutlook(WeatherForecast $weather = null) // Inject { $weather = new WeatherForecast(); $outlook = $weather->isSunny() ? "full" : "empty"; return "The glass is half $outlook."; } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP myLegacyCode.php function getOutlook(WeatherForecast $weather = null) { $weather = $weather ?? new WeatherForecast(); // Use injected dependency $outlook = $weather->isSunny() ? "full" : "empty"; return "The glass is half $outlook."; } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock('overload:WeatherForecast') ->shouldReceive('isSunny') ->andReturn(true); $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock(WeatherForecast::class) // No overload! ->shouldReceive('isSunny') ->andReturn(true); $result = getOutlook(); $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php public function testHalfFull() { $mockForecast = Mockery::mock(WeatherForecast::class) ->shouldReceive('isSunny') ->andReturn(true); $result = getOutlook($mockForecast); // Inject! $this->assertEquals('The glass is half full.', $result); // Success! } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP tests/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #4 Ungraceful exits

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #4 (a) Redirects

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP holyGrail.php function enterCaveOfCaerbannog(bool $killerRabbit = false) { if ($killerRabbit) { header('Location: http://www.montypython.com'); } return "Behold!"; } Redirections

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@maccath | Katy Ereira | #LonghornPHP tests/CaveOfCaerbannogTest.php class EnterCaveOfCaerbannogTest extends PHPUnit\Framework\TestCase { public function testEnterSafely() { enterCaveOfCaerbannog(); } public function testRunAway() { enterCaveOfCaerbannog($killerRabbit = true); } } Redirections

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@maccath | Katy Ereira | #LonghornPHP tests/CaveOfCaerbannogTest.php /** * @runTestsInSeparateProcesses */ class EnterCaveOfCaerbannogTest extends PHPUnit\Framework\TestCase { public function testEnterSafely() { … } public function testRunAway() { … } } Redirections

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@maccath | Katy Ereira | #LonghornPHP tests/CaveOfCaerbannogTest.php public function testEnterSafely() { $result = enterCaveOfCaerbannog(); $this->assertEquals('Behold!', $result); // Success! } Redirections

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@maccath | Katy Ereira | #LonghornPHP tests/CaveOfCaerbannogTest.php public function testRunAway() { $result = enterCaveOfCaerbannog($killerRabbit = true); $this->assertNotEquals('Behold!', $result); // Failure. } Redirections

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@maccath | Katy Ereira | #LonghornPHP Refactoring: Redirections ● Return/continue/break after (potentially) redirecting. or ● Set redirection header as the very last step.

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@maccath | Katy Ereira | #LonghornPHP holyGrail.php function enterCaveOfCaerbannog(bool $killerRabbit = false) { if (!$killerRabbit) { return "Behold!"; // Return early. } header('Location: http://www.montypython.com'); } Redirections

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #4 (b) Exiting

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP LizTruss.php function lizTruss(bool $quitter = false) { if (!$quitter) { return 'I am a fighter, not a quitter!'; } exit; } Exiting

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@maccath | Katy Ereira | #LonghornPHP tests/LizTrussTest.php class LizTest extends PHPUnit\Framework\TestCase { public function testNotAQuitter() { $result = lizTruss($quitter = false); } public function testIsAQuitter() { $result = lizTruss($quitter = true); } } Exiting

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@maccath | Katy Ereira | #LonghornPHP tests/LizTrussTest.php public function testNotAQuitter() { $result = lizTruss($quitter = false); $this->assertEquals('I am a fighter, not a quitter!', $result); } Exiting

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@maccath | Katy Ereira | #LonghornPHP tests/LizTrussTest.php public function testIsAQuitter() { $result = lizTruss($quitter = true); $this->assertEmpty($result); // We never get here. } Exiting

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@maccath | Katy Ereira | #LonghornPHP Refactoring: Exiting ● Create a wrapper around the exit functionality. ● Inject the exit wrapper. ● Safely refactor to use the exit wrapper. ● Mock the exit wrapper.

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@maccath | Katy Ereira | #LonghornPHP DowningStreet.php class DowningStreet { public function leave() { exit; // Leave the building. } } Exiting

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@maccath | Katy Ereira | #LonghornPHP LizTruss.php function lizTruss(bool $quitter = false, DowningStreet $no10 = null) // Inject { if (!$quitter) { … } exit; } Exiting

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@maccath | Katy Ereira | #LonghornPHP LizTruss.php function lizTruss(bool $quitter = false, DowningStreet $no10 = null) { $no10 = $no10 ?? new DowningStreet(); // Set default. if (!$quitter) { … } exit; } Exiting

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@maccath | Katy Ereira | #LonghornPHP LizTruss.php function lizTruss(bool $quitter = false, DowningStreet $downingSt = null) { $no10 = $no10 ?? new DowningStreet(); if (!$quitter) { … } $no10->leave(); // Leave. } Exiting

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@maccath | Katy Ereira | #LonghornPHP tests/LizTrussTest.php public function testIsAQuitter() { $no10 = Mockery::mock(DowningStreet::class); // Mock no10. $result = lizTruss($quitter = true); $this->assertEmpty($result); // Failure. } Exiting

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@maccath | Katy Ereira | #LonghornPHP LizTruss.php public function testLizTruss() { $no10 = Mockery::mock(DowningStreet::class) ->shouldIgnoreMissing(); // Do nothing... $result = lizTruss($quitter = true); $this->assertEmpty($result); // Failure. } Exiting

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@maccath | Katy Ereira | #LonghornPHP tests/LizTrussTest.php public function testLizTruss() { $no10 = Mockery::mock(DowningStreet::class) ->shouldIgnoreMissing(); $result = lizTruss($quitter = true, $no10); $this->assertEmpty($result); // Success! } Exiting

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #5 Filesystem interaction

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP HitCounter.php function countHit() { $count = file_get_contents(__DIR__ . '/hit_counter.txt'); file_put_contents(__DIR__ . '/hit_counter.txt', ++$count); } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php class HitCounterTest extends PHPUnit\Framework\TestCase { public function testCountsHit() { countHit(); } } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function testCountsHit() { $hitCounterFile = __DIR__ . '/../hit_counter.txt'; $countBefore = file_get_contents($hitCounterFile); countHit(); $countAfter = file_get_contents($hitCounterFile); $this->assertEquals($countBefore++, $countAfter); // Success! } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP Refactoring: Updating a file ● Inject the filename. ● Create a test double hit counter file. ● Reset the file contents after each test.

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@maccath | Katy Ereira | #LonghornPHP HitCounter.php function countHit($file = __DIR__ . '/hit_counter.txt') // Inject $file { $count = file_get_contents(__DIR__ . '/hit_counter.txt'); file_put_contents(__DIR__ . '/hit_counter.txt', ++$count); } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP HitCounter.php function countHit($file = __DIR__ . '/hit_counter.txt') // Inject $file { $count = file_get_contents($file); // Use $file file_put_contents($file, ++$count); // Use $file } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/Unit/HitCounterTest.php public function testCountsHit() { $hitCounterFile = __DIR__ . '/hit_counter.txt'; $countBefore = file_get_contents($hitCounterFile); countHit(); $countAfter = file_get_contents($hitCounterFile); $this->assertEquals($countBefore++, $countAfter); } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function testCountsHit() { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; // Test file! $countBefore = file_get_contents($hitCounterFile); countHit(); $countAfter = file_get_contents($hitCounterFile); $this->assertEquals($countBefore++, $countAfter); } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function testCountsHit() { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; $countBefore = file_get_contents($hitCounterFile); countHit($hitCounterFile); // Use test hit counter file. $countAfter = file_get_contents($hitCounterFile); $this->assertEquals($countBefore++, $countAfter); } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function tearDown(): void { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; file_put_contents($hitCounterFile, 0); // Reset counter. } Updating a ﬁle

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@maccath | Katy Ereira | #LonghornPHP “ vfsStream is a stream wrapper for a virtual file system that may be helpful in unit tests to mock the real file system. It can be used with any unit test framework, like PHPUnit or SimpleTest. Fake filesystem Reference: http:/ /vfs.bovigo.org/

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function testCountsHit() { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; $countBefore = file_get_contents($hitCounterFile); countHit($hitCounterFile); $countAfter = file_get_contents($hitCounterFile); $this->assertEquals($countBefore++, $countAfter); } Fake ﬁlesystem

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@maccath | Katy Ereira | #LonghornPHP tests/HitCounterTest.php public function testCountsHit() { $vfs = vfsStream::setup(); $hitCounterFile = vfsStream::newFile('test_hit_counter.txt') ->at($vfs) ->setContent('0'); countHit($hitCounterFile->url()); $this->assertEquals(1, $hitCounterFile->getContent()); } Fake ﬁlesystem

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #6 Spaghetti code

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP Spaghetti code Bolognese.php class Bolognese { private $eaten; private $parmesan; public function __construct(bool $eaten = false) { … } public function eat() { … } public function isEaten(): bool { … } }

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@maccath | Katy Ereira | #LonghornPHP Spaghetti code Bolognese.php public function eat() { if ($this->eaten) return; // Can’t eat twice! if (!$this->parmesan || !$this->parmesan->isEaten()) { $this->parmesan = new Parmesan(); // Must always have parmesan. } (new GarlicBread())->eat(); // Gotta have garlic bread. $this->parmesan->eat(); $this->eaten = true; }

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php class BologneseTest extends PHPUnit\Framework\TestCase { public function testEat() { $bolognese = new Bolognese(); $bolognese->eat(); } } Spaghetti code

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php public function testEat() { $bolognese = new Bolognese(); $bolognese->eat(); $this->assertTrue($bolognese->isEaten()); } Spaghetti code

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@maccath | Katy Ereira | #LonghornPHP Testing: Spaghetti Code ● Use @covers annotation to isolate unit under test ● Create reusable expectations: ○ to illustrate diﬀerent scenarios ○ to deﬁne alternate process branches

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php /** * @covers Bolognese */ public function testEat() { $bolognese = new Bolognese(); $bolognese->eat(); $this->assertTrue($bolognese->isEaten()); } Testing: Spaghetti Code

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php public function testEatDevouredBolognese() { … } public function testEatUneatenBolognese() { … } Testing: Spaghetti Code

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php private function eatenBolognese() { return new Bolognese($eaten = true); } private function uneatenBolognese() { return new Bolognese($eaten = false); } Testing: Spaghetti Code

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php private function expectGarlicBreadToBeEaten() { $garlicBread = Mockery::mock('overload:GarlicBread'); return $garlicBread->shouldReceive('eat'); // Return expectation. } Testing: Spaghetti Code

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@maccath | Katy Ereira | #LonghornPHP tests/BologneseTest.php public function testEatDevouredBolognese() { $this->expectGarlicBreadToBeEaten()->never(); $this->eatenBolognese()->eat(); } public function testEatUneatenBolognese() { $this->expectGarlicBreadToBeEaten()->once(); $this->uneatenBolognese()->eat(); } Testing: Spaghetti Code

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@maccath | Katy Ereira | #LonghornPHP Tricky Test Scenario #7 Private methods

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@maccath | Katy Ereira | #LonghornPHP

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@maccath | Katy Ereira | #LonghornPHP Private methods MCHammer.php class MCHammer { public function stop() { return $this->cantTouchThis(); } private function cantTouchThis() { return 'hammertime'; } }

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@maccath | Katy Ereira | #LonghornPHP Private methods tests/MCHammerTest.php class MCHammerTest extends PHPUnit\Framework\TestCase { public function testCantTouchThis() { $mcHammer = new MCHammer(); $result = $mcHammer->cantTouchThis(); // Error; private method! $this->assertEquals('hammertime', $result); } }

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@maccath | Katy Ereira | #LonghornPHP Private methods ● Don’t test private methods. ● Test the public methods that use private methods. ● Private methods represent implementation details. ● Private methods should remain invisible.

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@maccath | Katy Ereira | #LonghornPHP Private methods tests/MCHammerTest.php class MCHammerTest extends PHPUnit\Framework\TestCase { public function testCantTouchThis() { $mcHammer = new MCHammer(); $result = $mcHammer->stop(); // Public method! $this->assertEquals('hammertime', $result); } }

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@maccath | Katy Ereira | #LonghornPHP Private methods tests/MCHammerTest.php class MCHammerTest extends PHPUnit\Framework\TestCase { public function testCantTouchThis() { $mcHammer = new MCHammer(); $result = $mcHammer->stop(); $this->assertEquals('hammertime', $result); // Success! } }

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@maccath | Katy Ereira | #LonghornPHP Time for a recap... ● Interfering output ● Static methods ● Hard-coded dependencies ● Ungraceful exits ● Filesystem interaction ● Spaghetti code ● Private methods

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@maccath | Katy Ereira | #LonghornPHP https://joind.in/talk/e0655