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Legacy Code - Testing and Safe Refactoring

Katy Ereira
February 07, 2020

Legacy Code - Testing and Safe Refactoring

Katy Ereira

February 07, 2020
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  1. @maccath | Katy Ereira | #SunPHP20
    Legacy Code.
    testing & safe refactoring

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  2. @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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  3. @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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  4. @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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  5. @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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  6. @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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  7. @maccath | Katy Ereira | #SunPHP20
    Paradox: can’t refactor
    untested code, but
    can’t test the code
    until it’s refactored.

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  8. @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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  9. @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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  10. @maccath | Katy Ereira | #SunPHP20
    Assumptions: you’re developing with PHP
    and you have access to a terminal with
    Composer.

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  11. @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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  12. @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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  13. @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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  14. @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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  15. @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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  16. @maccath | Katy Ereira | #SunPHP20
    Mocking
    ● Create test doubles
    ● Verify the behaviour of your code
    ● Isolate the system under test

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  17. @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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  18. @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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  19. @maccath | Katy Ereira | #SunPHP20
    Install via Composer:
    $ composer require --dev mockery/mockery
    Mockery - Installation

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  20. @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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  21. @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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  22. @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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  23. @maccath | Katy Ereira | #SunPHP20
    Disclaimer: the following examples are
    deliberately simple.

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

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  25. @maccath | Katy Ereira | #SunPHP20

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  26. @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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  27. @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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  28. @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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  29. @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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  30. @maccath | Katy Ereira | #SunPHP20
    tests/YodelTest.php
    public function testNewYodel()
    {
    ob_start(); // Start capturing output.
    yodel();
    }
    A method that echoes

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  31. @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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  32. @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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  33. @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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  34. @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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  35. @maccath | Katy Ereira | #SunPHP20
    Tricky Test Scenario #2
    Static method calls

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  36. @maccath | Katy Ereira | #SunPHP20

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  37. @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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  38. @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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  39. @maccath | Katy Ereira | #SunPHP20
    Goku.php
    class Goku
    {
    static function powerLevel()
    {
    return 5000; // Always returns 5000.
    }
    }
    A static method call

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  40. @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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  41. @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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  42. @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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  43. @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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  44. @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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  45. @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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  46. @maccath | Katy Ereira | #SunPHP20

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

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

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  49. @maccath | Katy Ereira | #SunPHP20

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  50. @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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  51. @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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  52. @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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  53. @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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  54. @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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  55. @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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  56. @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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  57. @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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  58. @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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  59. @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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  60. @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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  61. @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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  62. @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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  63. @maccath | Katy Ereira | #SunPHP20
    tests/OutlookTest.php
    /**
    * @runTestsInSeparateProcesses
    * @preserveGlobalState disabled
    */
    class OutlookTest extends PHPUnit\Framework\TestCase
    {
    // ...
    }
    A hard-coded dependency

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  64. @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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  65. @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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  66. @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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  67. @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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  68. @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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  69. @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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  70. @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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  71. @maccath | Katy Ereira | #SunPHP20
    tests/OutlookTest.php
    /**
    * @runTestsInSeparateProcesses
    */
    class OutlookTest extends PHPUnit\Framework\TestCase
    {
    // ...
    }
    A hard-coded dependency

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

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

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

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  75. @maccath | Katy Ereira | #SunPHP20

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  76. @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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  77. @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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  78. @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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  79. @maccath | Katy Ereira | #SunPHP20
    tests/CaveOfCaerbannogTest.php
    public function testEnterSafely()
    {
    $result = enterCaveOfCaerbannog();
    $this->assertEquals('Behold!', $result); // Success!
    }
    Redirections

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

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  81. @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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  82. @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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  83. @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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  84. @maccath | Katy Ereira | #SunPHP20
    tests/CaveOfCaerbannogTest.php
    public function testRunAway()
    {
    $result = enterCaveOfCaerbannog($killerRabbit = true);
    $this->assertEmpty($result); // Success!
    }
    Redirections

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

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  86. @maccath | Katy Ereira | #SunPHP20

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

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  88. @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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  89. @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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  90. @maccath | Katy Ereira | #SunPHP20
    tests/BrexitTest.php
    public function testBrexit()
    {
    $result = brexit();
    $this->assertEmpty($result); // We never get here.
    }
    Exiting

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

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

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  94. @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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  95. @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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  96. @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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  97. @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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  98. @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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  99. @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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  100. @maccath | Katy Ereira | #SunPHP20
    Tricky Test Scenario #5
    Filesystem interaction

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  101. @maccath | Katy Ereira | #SunPHP20

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

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  104. @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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  105. @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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  106. @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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  107. @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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  108. @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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  109. @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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  110. @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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  111. @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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  112. @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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  113. @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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  114. @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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  115. @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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  116. @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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  117. @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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  118. @maccath | Katy Ereira | #SunPHP20
    Tricky Test Scenario #6
    Spaghetti code

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  119. @maccath | Katy Ereira | #SunPHP20

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  120. @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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  121. @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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  122. @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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  123. @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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  124. @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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  125. @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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  126. @maccath | Katy Ereira | #SunPHP20
    tests/BologneseTest.php
    public function testEatDevouredBolognese() { … }
    public function testEatUneatenBolognese() { … }
    Testing: Spaghetti Code

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  127. @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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  128. @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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  129. @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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  130. @maccath | Katy Ereira | #SunPHP20
    Tricky Test Scenario #7
    Private methods

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  131. @maccath | Katy Ereira | #SunPHP20

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  132. @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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  133. @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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  134. @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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  135. @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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  136. @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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  137. @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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  138. @maccath | Katy Ereira | #SunPHP20
    https://joind.in/talk/7243c

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