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@maccath | Katy Ereira | #SunPHP20 Legacy Code. testing & safe refactoring

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Paradox: can’t refactor untested code, but can’t test the code until it’s refactored.

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Assumptions: you’re developing with PHP and you have access to a terminal with Composer.

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@maccath | Katy Ereira | #SunPHP20 “ 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, 7.4 Future release 8 7.2, 7.3, 7.4 February 5, 2021 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 | #SunPHP20 Mocking ● Create test doubles ● Verify the behaviour of your code ● Isolate the system under test

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 “ 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 | #SunPHP20 Install via Composer: $ composer require --dev mockery/mockery Mockery - Installation

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@maccath | Katy Ereira | #SunPHP20 Mockery - Usage tests/ExampleTest.php class ExampleTest extends PHPUnit\Framework\TestCase { public function setUp(): void { $mockObject = Mockery::mock(Object::class); } }

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Disclaimer: the following examples are deliberately simple.

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #1 Interfering Output

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 ● 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 | #SunPHP20 tests/YodelTest.php public function testNewYodel() { ob_start(); // Start capturing output. yodel(); } A method that echoes

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Tricky Test Scenario #2 Static method calls

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Goku.php class Goku { static function powerLevel() { return 5000; // Always returns 5000. } } A static method call

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@maccath | Katy Ereira | #SunPHP20 tests/PowerLevelTest.php public function testUnder9000() { $result = getPowerLevel(); $this->assertEquals('Suppressed.', $result); // Success! } A static method call

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 A static method call tests/PowerLevelTest.php /** * @runTestsInSeparateProcesses * @preserveGlobalState disabled */ class PowerLevelTest extends PHPUnit\Framework\TestCase { // ... }

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #3 Hard-coded dependencies

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/OutlookTest.php /** * @runTestsInSeparateProcesses * @preserveGlobalState disabled */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #SunPHP20 ● 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #SunPHP20 tests/OutlookTest.php /** * @runTestsInSeparateProcesses */ class OutlookTest extends PHPUnit\Framework\TestCase { // ... } A hard-coded dependency

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #4 Ungraceful exits

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #4 (a) Redirects

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/CaveOfCaerbannogTest.php /** * @runTestsInSeparateProcesses */ class EnterCaveOfCaerbannogTest extends PHPUnit\Framework\TestCase { public function testEnterSafely() { … } public function testRunAway() { … } } Redirections

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@maccath | Katy Ereira | #SunPHP20 tests/CaveOfCaerbannogTest.php public function testEnterSafely() { $result = enterCaveOfCaerbannog(); $this->assertEquals('Behold!', $result); // Success! } Redirections

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@maccath | Katy Ereira | #SunPHP20 tests/CaveOfCaerbannogTest.php public function testRunAway() { $result = enterCaveOfCaerbannog($killerRabbit = true); $this->assertNotEquals('Behold!', $result); // Failure. } Redirections

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@maccath | Katy Ereira | #SunPHP20 Refactoring: Redirections ● Return/continue/break after (potentially) redirecting. or ● Set redirection header as the very last step.

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@maccath | Katy Ereira | #SunPHP20 holyGrail.php function enterCaveOfCaerbannog(bool $killerRabbit = false) { if ($killerRabbit) { header('Location: http://www.montypython.com'); return; // Go no further! } return "Behold!"; } Redirections

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 tests/CaveOfCaerbannogTest.php public function testRunAway() { $result = enterCaveOfCaerbannog($killerRabbit = true); $this->assertEmpty($result); // Success! } Redirections

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #4 (b) Exiting

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 Brexit.php function brexit(bool $remainer = false) { if ($remainer) { return 'Bollocks to Brexit!'; } exit; } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/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 | #SunPHP20 tests/BrexitTest.php public function testRemainer() { $result = brexit($remainer = true); $this->assertEquals('Bollocks to Brexit!', $result); // Success! } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/BrexitTest.php public function testBrexit() { $result = brexit(); $this->assertEmpty($result); // We never get here. } Exiting

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 Boris.php class Boris { public function getBrexitDone() { exit; // Completely exits. } } Exiting

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@maccath | Katy Ereira | #SunPHP20 Brexit.php function brexit(bool $remainer, Boris $boris = null) // Inject { if ($remainer) { … } exit; } Exiting

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@maccath | Katy Ereira | #SunPHP20 Brexit.php function brexit(bool $remainer, Boris $boris = null) { $boris = $boris ?? new Boris(); // Set default. if ($remainer) { … } exit; } Exiting

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@maccath | Katy Ereira | #SunPHP20 Brexit.php function brexit(bool $remainer, Boris $boris = null) { $boris = $boris ?? new Boris(); if ($remainer) { … } $boris->getBrexitDone(); // Be Boris. } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class); // Mock Boris. $result = brexit(); $this->assertEmpty($result); // Failure. } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); // Do nothing... $result = brexit(); $this->assertEmpty($result); // Failure. } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); $result = brexit($remainer = false, $mockBoris); // Use Boris. $this->assertEmpty($result); // Success! } Exiting

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@maccath | Katy Ereira | #SunPHP20 tests/BrexitTest.php public function testBrexit() { $mockBoris = Mockery::mock(Boris::class) ->shouldIgnoreMissing(); $result = brexit($remainer = false, $mockBoris); $this->assertEmpty($result); // Success! } Exiting

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@maccath | Katy Ereira | #SunPHP20 Tricky Test Scenario #5 Filesystem interaction

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 tests/HitCounterTest.php class HitCounterTest extends PHPUnit\Framework\TestCase { public function testCountsHit() { countHit(); } } Updating a file

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 “ 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/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 | #SunPHP20 tests/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 | #SunPHP20 Tricky Test Scenario #6 Spaghetti code

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/BologneseTest.php public function testEat() { $bolognese = new Bolognese(); $bolognese->eat(); $this->assertTrue($bolognese->isEaten()); } Spaghetti code

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 tests/BologneseTest.php public function testEatDevouredBolognese() { … } public function testEatUneatenBolognese() { … } Testing: Spaghetti Code

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 Tricky Test Scenario #7 Private methods

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@maccath | Katy Ereira | #SunPHP20

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@maccath | Katy Ereira | #SunPHP20 Private methods MCHammer.php class MCHammer { public function stop() { return $this->cantTouchThis(); } private function cantTouchThis() { return 'hammertime'; } }

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@maccath | Katy Ereira | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 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 | #SunPHP20 https://joind.in/talk/7243c