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@maccath | Katy Ereira | #ScotPHP19 Legacy Code. testing & safe refactoring

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@maccath | Katy Ereira | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 Paradox: can’t refactor untested code, but can’t test the code until it’s refactored.

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@maccath | Katy Ereira | #ScotPHP19 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 | #ScotPHP19 A better solution 1. Perform just enough refactoring to make the code testable 2. Test the code 3. Refactor the code further 4. Profit!

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@maccath | Katy Ereira | #ScotPHP19 Assumptions: you’re developing with PHP and you have access to a terminal with Composer.

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@maccath | Katy Ereira | #ScotPHP19 “ 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 9 7.3 Future release 8 7.2 February 5, 2021 7 7.1 February 7, 2020 6 7.0 [unsupported] February 8, 2019 5 5.6 [unsupported] 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 | #ScotPHP19 “ 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 | #ScotPHP19 Install via Composer: $ composer require --dev mockery/mockery Mockery - Installation

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@maccath | Katy Ereira | #ScotPHP19 Mockery - Usage tests/Unit/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function setUp(): void { $mockObject = Mockery::mock(Object::class); } }

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@maccath | Katy Ereira | #ScotPHP19 Mockery - Usage tests/Unit/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 } } tests/Unit/ExampleTest.php

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@maccath | Katy Ereira | #ScotPHP19 Mockery - Usage tests/Unit/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function tearDown(): void { Mockery::close(); // Always close after running tests! } } tests/Unit/ExampleTest.php

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@maccath | Katy Ereira | #ScotPHP19 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 | #ScotPHP19 Disclaimer: the following examples are deliberately simple.

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #1 Interfering Output

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 A method that echoes tests/Unit/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 | #ScotPHP19 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 | #ScotPHP19 ● 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 | #ScotPHP19 tests/Unit/YodelTest.php public function testNewYodel() { ob_start(); // Start capturing output. yodel(); } A method that echoes

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 Tricky Test Scenario #2 Hard-coded dependencies

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #2a Static method calls

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 Goku.php class Goku { static function powerLevel() { return 5000; // Always returns 5000. } } A static method call

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/PowerLevelTest.php public function testUnder9000() { $result = getPowerLevel(); $this->assertEquals('Suppressed.', $result); // Success! } A static method call

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/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 | #ScotPHP19 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 | #ScotPHP19 A static method call tests/Unit/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 | #ScotPHP19 A static method call tests/Unit/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 | #ScotPHP19 A static method call tests/Unit/PowerLevelTest.php /** * @runTestsInSeparateProcesses */ class PowerLevelTest extends PHPUnit\Framework\TestCase { // ... }

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@maccath | Katy Ereira | #ScotPHP19 A static method call tests/Unit/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 | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 “ A static method call - via a Facade Unlike traditional static method calls, facades may be mocked. This provides a great advantage over traditional static methods and grants you the same testability you would have if you were using dependency injection. Reference: https:/ /laravel.com/docs/5.8/mocking#mocking-facades

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@maccath | Katy Ereira | #ScotPHP19 A static method call - via a Facade tests/Unit/PowerLevelTest.php public function testOver9000() { $superSaiyanGoku = 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 | #ScotPHP19 A static method call - via a Facade tests/Unit/PowerLevelTest.php public function testOver9000() { // Goku is super saiyan! Goku::shouldReceive('powerLevel') ->andReturn(9001); . $result = getPowerLevel(); $this->assertEquals('It’s over 9000!', $result); // Success! }

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@maccath | Katy Ereira | #ScotPHP19 A static method call - via a Facade tests/Unit/PowerLevelTest.php /** * @runTestsInSeparateProcesses */ class PowerLevelTest extends TestCase { // ... }

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@maccath | Katy Ereira | #ScotPHP19 A static method call - via a Facade tests/Unit/PowerLevelTest.php /** * @runTestsInSeparateProcesses */ class PowerLevelTest extends TestCase { // ... }

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #2b Making new objects on the fly

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 A hard-coded dependency ● 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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #ScotPHP19 ● 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 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 | #ScotPHP19 tests/Unit/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #3 Ungraceful exits

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #3a Redirects

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function getMeOutOfHere(bool $imACelebrity = false) { if ($imACelebrity) { header('Location: http://google.com'); } return "Nope!"; } Redirections

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/GetMeOutTest.php class GetMeOutTest extends PHPUnit\Framework\TestCase { public function testLeaveMeHere() { getMeOutOfHere(); } public function testGetMeOut() { getMeOutOfHere($imACelebrity = true); } } Redirections

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/GetMeOutTest.php /** * @runTestsInSeparateProcesses */ class GetMeOutTest extends PHPUnit\Framework\TestCase { public function testLeaveMeHere() { … } public function testGetMeOut() { … } } Redirections

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/GetMeOutTest.php public function testLeaveMeHere() { $result = getMeOutOfHere(); $this->assertEquals('Nope!', $result); // Success! } Redirections

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/GetMeOutTest.php public function testGetMeOut() { $result = getMeOutOfHere($imACelebrity = true); $this->assertNotEquals('Nope!', $result); // Failure. } Redirections

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@maccath | Katy Ereira | #ScotPHP19 Refactoring: Redirections ● Return/continue/break after (potentially) redirecting. or ● Set redirection header as the very last step.

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function getMeOutOfHere(bool $imACelebrity = false) { if ($imACelebrity) { header('Location: http://google.com'); return; // Don’t go any further! } return "Nope!"; } Redirections

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function getMeOutOfHere(bool $imACelebrity = false) { if (!$imACelebrity) { return "Nope!"; // Return early. } header('Location: http://google.com'); } Redirections

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/GetMeOutTest.php public function testGetMeOut() { $result = getMeOutOfHere($imACelebrity = true); $this->assertNotEquals('Nope!', $result); // Success! } Redirections

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #3b Exiting

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function brexit(bool $remainer = false) { if ($remainer) { return 'People’s vote!'; } exit; } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php class BrexitTest extends PHPUnit\Framework\TestCase { public function testBrexit() { $result = brexit(); } public function testRemainer() { $result = brexit($remainer = true); } } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testRemainer() { $result = brexit($remainer = true); $this->assertEquals('People’s vote!', $result); // Success! } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testBrexit() { $result = brexit(); $this->assertEmpty($result); // Never gets here. } Exiting

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@maccath | Katy Ereira | #ScotPHP19 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 | #ScotPHP19 Boris.php class Boris { public function brexitMeansBrexit() { exit; // Completely exits. } } Exiting

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function brexit(bool $remainer, Boris $boris = null) // Inject { if ($remainer) { … } exit; } Exiting

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function brexit(bool $remainer, Boris $boris = null) { $boris = $boris ?? new Boris(); // Set default. if ($remoaner) { … } exit; } Exiting

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.php function brexit(bool $remainer, Boris $boris = null) { $boris = $boris ?? new Boris(); if ($remainer) { … } $boris->brexitMeansBrexit(); // Be Boris. } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class); // Mock Boris $result = brexit(); $this->assertNotEquals('People’s vote!', $result); // Failure. } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); // Do nothing... $result = brexit(); $this->assertNotEquals('People’s vote!', $result); // Failure. } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); $result = brexit($remainer = false, $mockBoris); // Use Boris. $this->assertNotEquals('People’s vote!', $result); // Success! } Exiting

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); $result = brexit($remainer = false, $mockBoris); $this->assertNotEquals('People’s vote!', $result); // Success! } Exiting

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #4 The filesystem

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 tests/Unit/HitCounterTest.php class HitCounterTest extends PHPUnit\Framework\TestCase { public function testCountsHit() { countHit(); } } Updating a file

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@maccath | Katy Ereira | #ScotPHP19 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); // Success! } Updating a file

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@maccath | Katy Ereira | #ScotPHP19 Refactoring: Updating a file ● Inject the filename. ● Create a test hit counter file. ● Reset the file contents after each test.

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@maccath | Katy Ereira | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 myLegacyCode.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 | #ScotPHP19 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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 “ 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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/HitCounterTest.php public function tearDown(): void { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; file_put_contents($hitCounterFile, 0); // Reset counter. } Fake filesystem

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/HitCounterTest.php public function tearDown(): void { $hitCounterFile = __DIR__ . '/test_hit_counter.txt'; file_put_contents($hitCounterFile, 0); // Reset counter. } Fake filesystem

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@maccath | Katy Ereira | #ScotPHP19 Tricky Test Scenario #5 Spaghetti code

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 Spaghetti code src\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 | #ScotPHP19 Spaghetti code src\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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/BologneseTest.php public function testEat() { $bolognese = new Bolognese(); $bolognese->eat(); $this->assertTrue($bolognese->isEaten()); } Spaghetti code

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@maccath | Katy Ereira | #ScotPHP19 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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/BologneseTest.php public function testEatDevouredBolognese() { … } public function testEatUneatenBolognese() { … } Testing: Spaghetti Code

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@maccath | Katy Ereira | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 tests/Unit/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 | #ScotPHP19 Tricky Test Scenario Group #6 Private methods

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@maccath | Katy Ereira | #ScotPHP19

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@maccath | Katy Ereira | #ScotPHP19 Private methods MCHammer.php class MCHammer { public function stop() { return $this->cantTouchThis(); } private function cantTouchThis() { return 'hammertime'; } }

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@maccath | Katy Ereira | #ScotPHP19 Private methods tests/Unit/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 | #ScotPHP19 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 | #ScotPHP19 Private methods tests/Unit/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 | #ScotPHP19 Private methods tests/Unit/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 | #ScotPHP19 Thank ye!