Let your tests drive your code

Let your tests drive your
development
An in2it workshop
in it2PROFESSIONAL PHP SERVICES

in2it training - www.in2it.be - @in2itvof - #in2tdd Let your tests drive your development
Agenda
2
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

Agenda
3
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

What is test-driven development (TDD)?
Write unit tests ﬁrst
They will fail
Write functional code in accordance of the tests
Your tests will structure the way you write your code
Re-run your tests again
They should pass
4

System’s Check
5

Some conventions
PHPUnit was installed using composer
All vendor packages were installed with the code base
Running PHPUnit with ./vendor/bin/phpunit
If you use a different approach, make sure it works for you
GIT is used for the exercises, make sure you know about
checking out branches
reading git logs
In the slides I left out comments to save space
6

Simple example
Functional requirement
Write a small PHP class with a method that will return the string “Hello
World!”
7

Simple example
PHPUnit test
<?php
namespace AppTest;
use PHPUnitFrameworkTestCase;  
use AppHelloWorld;
class HelloWorldTest extends TestCase  
{
public function testAppOutputsHelloWorld()
{
$helloWorld = new HelloWorld();
$expectedAnswer = $helloWorld->sayHello();
$this->assertSame('Hello World!', $expectedAnswer);
}
}
8

Simple example
Running unit tests
9

Simple example
Writing the code
<?php
namespace App;
class HelloWorld  
{  
public function sayHello(): string  
{  
return 'Hello World!';  
}  
}
10

Simple example
Re-run unit tests
11

Change requests
13

Simple example
Change request
Update our small PHP class method that will allow an argument and will
return the string “Hello <arg>!” where <arg> is the argument provided.
14

Simple example
Options
15

Simple example
Why change the existing test?
Code change so test has to change
New requirements change the test goal
16

Simple example
Why not change the existing test?
Code requirement change so new test is required
We don’t want to change existing requirements
Prevent BC breaks
New test will cover changing requirements
17

Simple example
New test case
public function testAppOutputsHelloArgument()  
{  
$helloWorld = new HelloWorld();  
$expectedAnswer = $helloWorld->sayHello('unit testers');  
$this->assertSame('Hello unit testers!', $expectedAnswer);  
}
18

Simple example
Running unit tests
19

Simple example 
Changing the code
<?php
namespace App;
{  
public function sayHello(string $arg): string  
{  
return 'Hello ' . $arg . '!';  
}  
}
20

Simple example
Re-run the tests
21

We introduced an error now!
22

Simple example
Finding the bug
<?php
namespace App;
{  
public function sayHello(string $arg): string  
{  
return 'Hello ' . $arg . '!';  
}  
}
23
No default value

Simple example
Fixing failure
<?php
namespace App;
class HelloWorld
{
public function sayHello(string $arg = 'World'): string
{
return 'Hello ' . $arg . '!';
}
}
24

Simple example
Re-run the tests
25

Simple example
Recap
Write test based on functionality (and run test)
Write code based on functionality (and re-run test)
Write new test based on changed functionality (and re-run tests)
Change code based on functionality (and re-run tests)
Update code until all tests are passing
27

Simple example
Get the source code
Go to the project folder and use the following commands
git checkout simple-example 
./vendor/bin/phpunit
All ﬁles will be there, so review them closely
28

in2it training - www.in2it.be - @in2itvof - #in2tdd Let your tests drive your development29
Exercise
New change requirements
Security is important, so we need to validate the
given argument so it only accepts string type
values. If something other than a string is
provided, an exception should be raised.
10 minutes

Agenda
30
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

Project “TodoToDone”
Project “TodoToDone” is a simple todo tool, tracking the tasks that you need
to do. It should provide the following features:
List open tasks sorted newest to oldest
Create a new task (label and description)
Update an existing task
Mark task as done in the overview list
Remove task marked as done
31

Requirements as skeleton
<?php
namespace AppTestService;
use PHPUnitFrameworkTestCase;
class TaskServiceTest extends TestCase
{
    public function testServiceReturnsListOfTasks()
    {
        // List open tasks sorted newest to oldest
    }
    public function testServiceCanAddNewTask()
    {
        // Create a new task (label and description)
    }
    public function testServiceCanUpdateExistingTask()
    {
        // Update an existing task
    }
    public function testServiceCanMarkTaskAsDone()
    {
        // Mark task as done in the overview list
    }
    public function testServiceCanRemoveTaskMarkedAsDone()
    {
        // Remove task marked as done
    }
}
32

Don’t start writing test yet!
Unit testing is about looking at a speciﬁc task from every angle
Deﬁne use and edge cases and add them as additional tests
33

Example edge cases
public function testServiceWillThrowRuntimeExceptionWhenStorageFailsToFetchTaskList()
{
    // Throw a runtime exception when connection to storage fails for fetching task list
}
public function testServiceWillThrowInvalidArgumentExceptionWhenInvalidTaskIsAdded()
{
    // Throw an invalid argument exception for invalid task when adding
}
public function testServiceWillThrowRuntimeExceptionWhenStorageFails()
{
    // Throw a runtime exception when storage of task fails
}
public function testServiceWillThrowDomainExceptionWhenTaskWasMarkedAsDoneWhenMarkingTaskAsDone()
{
    // Throw a domain exception when a task was already marked as done
}
34

Question
Why am I using very long and explicit method names for
my test methods?

Answer
To have human readable documentation about the features we’re developing and testing.
./vendor/bin/phpunit --testdox

TestDox output
PHPUnit 6.1.3 by Sebastian Bergmann and contributors.
AppTestServiceTaskService
[ ] Service returns list of tasks
[ ] Service can add new task
[ ] Service throws exception if task was not found
[ ] Service can ﬁnd task
[ ] Service can remove task
[ ] Service can update existing task
[ ] Service can mark task as done
[ ] Service can remove task marked as done
[ ] Service will throw type error when invalid task is added
[ ] Service will throw domain exception when done task gets marked done
37

Exercise
Complete the test cases
git checkout tdd-ex1
Go and check out branch tdd-ex1 where you will
ﬁnd the code as we’ve seen thus far.
Pro tip: complete 1 test and commit, this way
you also learn to commit small and commit
often.
20 minutes

How we’re approaching this
We need to “prepare” our test class
Create a “setUp” method to create a fixture
Create a “tearDown” method to unset the fixture
Implement first test “testServiceReturnsListOfTasks”
Making use of fixture to mimic actual behaviour
Create class interfaces for structure
Implement concrete class
39

Preparing our 1st test
40

{
    protected $taskGateway;
    protected function setUp()
    {
        parent::setUp();
        $taskEntity = $this->getMockBuilder(TaskEntityInterface::class)
            ->setMethods(['getId', 'getLabel', 'getDescription', 'isDone', 'getCreated', 'getModified'])->getMock();
        $taskEntry1 = clone $taskEntity;
        $taskEntry1->method('getId')->willReturn('123');
        $taskEntry1->method('getLabel')->willReturn('Task #123');
        $taskEntry1->method('getDescription')->willReturn('#123: This is task 123');
        $taskEntry1->method('isDone')->willReturn(false);
        $taskEntry1->method('getCreated')->willReturn(new DateTime('2017-03-21 07:53:24'));
        $taskEntry1->method('getModified')->willReturn(new DateTime('2017-03-21 08:16:53'));
        $taskCollection = new SplObjectStorage();
        $taskCollection->attach($taskEntry3);
        $taskGateway = $this->getMockBuilder(TaskGatewayInterface::class)->setMethods(['fetchAll'])->getMock();
        $taskGateway->expects($this->any())->method('fetchAll')->willReturn($taskCollection);
        $this->taskGateway = $taskGateway;
    }
    /* ... */
}
41

{
    /* ... */
    protected function tearDown()
    {
        unset ($this->taskGateway);
    }
    /* ... */
}
42

{
    /* ... */
    /**
     * List open tasks sorted newest to oldest
     *
     * @covers TaskService::fetchAll
     */
    public function testServiceReturnsListOfTasks()
    {
        $taskService = new TaskService($this->taskGateway);
        $taskList = $taskService->getAllTasks();
        $this->assertInstanceOf(Iterator::class, $taskList);
        $this->assertGreaterThan(0, count($taskList));
        $taskList->rewind();
        $previous = null;
        while ($taskList->valid()) {
            if (null !== $previous) {
                $current = $taskList->current();
                $this->assertTrue($previous->getCreated() > $current->getCreated());
            }
            $previous = $taskList->current();
            $taskList->next();
        }
    }
    /* ... */
}
43

Creating gateway interface
<?php
namespace AppModel;
interface TaskGatewayInterface
{
    /**
     * Fetch all tasks from the back-end storage
     * @return Iterator
     */
    public function fetchAll(): Iterator;
}
44

Creating entity interface
<?php
namespace AppModel;
interface TaskEntityInterface
{
    public function getId(): string;
    public function getLabel(): string;
    public function getDescription(): string;
    public function isDone(): bool;
    public function getCreated(): DateTime;
    public function getModified(): DateTime;
}
45

Exercise
Check out the ﬁnished test cases
ﬁnd the completed test cases.
Make sure you also check out the GIT logs as I
used 27 commits to explain what was happening
and why!
10 minutes

{
parent::setUp();
// We create a mock object
$taskEntity = $this->getMockBuilder(TaskEntityInterface::class)
->setMethods(['getId', 'getLabel', 'getDescription', 'isDone', 'getCreated', 'getModified', 'setLabel', 'setDone'])
->getMock();
$taskEntryUpdate = clone $taskEntity;
$taskEntryUpdate->method('getId')->willReturn('123');
$taskEntryUpdate->method('getLabel')->willReturn('Task #123: Update from service');
$taskEntryUpdate->method('getDescription')->willReturn('#123: This is task 123');
$taskEntryUpdate->method('isDone')->willReturn(false);
$taskEntryUpdate->method('getCreated')->willReturn(new DateTime('2017-03-21 07:53:24'));
$taskEntryUpdate->method('getModified')->willReturn(new DateTime('now'));
$taskEntry2->method('isDone')->willReturn(true);
$taskEntryDone = clone $taskEntity;
$taskEntryDone->method('getId')->willReturn('789');
$taskEntryDone->method('getLabel')->willReturn('#789');
$taskEntryDone->method('getDescription')->willReturn('#789: This is task 789');
$taskEntryDone->method('isDone')->willReturn(true);
$taskEntryDone->method('getCreated')->willReturn(new DateTime('2017-04-23 07:53:24'));
$taskEntryDone->method('getModified')->willReturn(new DateTime('now'));
48

Magic happening in setUp
Ideal place to set things up (using ﬁxtures)
Stub is shared among different test methods
Now all is ready to be implemented as we secured the code-base
49

Project status
[x] Service returns list of tasks
[x] Service can add new task
[x] Service throws exception if task was not found
[x] Service can ﬁnd task
[x] Service can remove task
[x] Service can update existing task
[x] Service can mark task as done
[x] Service can remove task marked as done
[x] Service will throw type error when invalid task is added
[x] Service will throw domain exception when done task gets marked done
50

Exercise
Check out the ﬁnished test cases
ﬁnd the other completed test cases.
15 minutes

TextDox output
PHPUnit 6.1.3 by Sebastian Bergmann and contributors.
AppTestModelTaskEntity
[x] Task entity is empty at construction
[x] Task entity throws error when constructed with wrong type
of arguments
[x] Task entity throws exception when constructed with wrong
arguments
[x] Task entity accepts correct arguments
AppTestModelTaskGateway
[x] Fetch all returns iterator object
[x] Gateway can add task entity
[x] Find returns null when nothing found
[x] Find returns task entity when result is found
[x] Gateway can remove task entity
[x] Gateway can update task entity
[x] Service returns list of tasks
[x] Service can add new task
[x] Service throws exception if task was not found
[x] Service can ﬁnd task
[x] Service can remove task
[x] Service can update existing task
[x] Service can mark task as done
[x] Service can remove task marked as done
[x] Service will throw type error when invalid task is added
[x] Service will throw domain exception when done task gets
marked done
53

Exercise
Check out the web app
php -S localhost:8000 -t web web/index.php
ﬁnd the other completed test cases.
Run the web application using PHP’s build-in
web server to see how the app is behaving.
15 minutes

Conclusion
Let’s recap what has happened here
Writing test-ﬁrst gives you a clean scope of what
your code should do.
You have a more precise code-base that’s easy
to maintain, upgrade and is independent.

Agenda
60
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

Legacy challenges
Not (always) written with testing in mind
Dependencies make it hard to change code
Refactoring is often required before proper testing can start
For refactoring tests are required to ensure the refactored code
behaves the same!
61

Example project: EPESI
62

Tests?!?
64

How to get started?
65

Getting ready to test!
<?xml version="1.0" encoding="UTF-8" ?>
<phpunit
bootstrap="vendor/autoload.php"
colors="true"
stopOnErrors="true"
stopOnFailures="true">
<testsuites>
<testsuite name="App unit tests">
<directory suffix="php">tests</directory>
</testsuite>
</testsuites>
<filter>
<whitelist>
<directory suffix="php">src</directory>
</whitelist>
</filter>
<logging>
<log type="coverage-html" target="build/coverage" lowUpperBound="35" highLowerBound="70"/>
</logging>
</phpunit>
66

ModuleManager::module_install
/**
* Includes file with module installation class.
*
* Do not use directly.
*
* @param string $module_class_name module class name - underscore separated
*/
public static final function include_install($module_class_name) {
    if(isset(self::$modules_install[$module_class_name])) return true;
    $path = self::get_module_dir_path($module_class_name);
    $file = self::get_module_file_name($module_class_name);
    $full_path = 'modules/' . $path . '/' . $file . 'Install.php';
    if (!file_exists($full_path)) return false;
    ob_start();
    $ret = require_once($full_path);
    ob_end_clean();
    $x = $module_class_name.'Install';
    if(!(class_exists($x, false)) ||
!array_key_exists('ModuleInstall',class_parents($x)))
        trigger_error('Module '.$path.': Invalid install file',E_USER_ERROR);
    self::$modules_install[$module_class_name] = new $x($module_class_name);
    return true;
}
67

Testing happily…
<?php
require_once __DIR__ . '/../src/ModuleManager.php';
class ModuleManagerTest extends TestCase
{
    /**
     * @covers ModuleManager::include_install
     */
    public function testModuleManagerCanLoadMailModule()
    {
        $result = ModuleManager::include_install('Mail');
        $this->assertTrue($result);
    }
}
68

Comment out the test
<?php
require_once __DIR__ . '/../src/ModuleManager.php';
{
    /**
     */
    /*public function testModuleManagerCanLoadMailModule()
    {
    }*/
}
70

Let’s look again, more closely
/**
*
*
*/
    ob_start();
    ob_end_clean();
    return true;
}
71

https://www.ﬂickr.com/photos/marcgbx/7803086292

Test ﬁrst condition
/**
*/
public function testReturnImmediatelyWhenModuleAlreadyLoaded()
{
    $module = 'Foo_Bar';
    ModuleManager::$modules_install[$module] = 1;
    $result = ModuleManager::include_install($module);
    $this->assertCount(1, ModuleManager::$modules_install);
}
73

https://www.ﬂickr.com/photos/christian_johannesen/2248244786

Test second condition
/**
*/
public function testReturnWhenModuleIsNotFound()
{
    $module = 'Foo_Bar';
    $this->assertFalse($result);
    $this->assertEmpty(ModuleManager::$modules_install);
}
77

/**
*
*
*/
    ob_start();
    ob_end_clean();
    return true;
}
79

/**
*
*
*/
    ob_start();
    ob_end_clean();
    return true;
}
79
self::$modules_install[$module_class_name]

Add a “setUp” method
{
    {
        ModuleManager::$modules_install = [];
    }

    /* ... */
}
80

https://www.ﬂickr.com/photos/evaekeblad/14780090550

Testing third condition
/**
* @expectedException Error
*/
public function testTriggerErrorWhenInstallClassDoesNotExists()
{
    $module = 'EssClient';
    $this->fail('Expecting loading module ' . $module . ' would trigger an error');
}
83

/**
*
*
*/
    ob_start();
    ob_end_clean();
    return true;
}
85

https://www.ﬂickr.com/photos/sis/2497912343
Dead Code

So this test…
/**
*/
{
}
88

… changes into this test
/**
*/
{
    $this->assertFalse($result);
}
89

https://www.ﬂickr.com/photos/fragiletender/5332586299

Testing fourth condition
/**
*/
public function testTriggerErrorWhenInstallClassIsNotRegistered()
{
    $module = 'IClient';
}
92

Completing all tests
95

Remove comment tags
/**
*/
public function testModuleManagerCanLoadMailModule()
{
}
96

Recap
Testing legacy code is not easy, but still possible
Approach the source-code with a bail-ﬁrst approach
Make sure you can “bail” the method as fast as possible
Start with the most important part of your code
Ask yourself “What costs us money if it breaks” ➡ test that ﬁrst!
99

Exercise
Check out these tests
git checkout legacy-0.1
Go and check out branch legacy-0.1 and
analyse the tests.
If you have XDebug installed, you can run
PHPUnit with code coverage.
15 minutes

What to do?
If your code doesn’t return values

/**
* Process Bank Payment files
*/
public function processBankPayments()
{
    $this->getLogger()->log('Starting bank payment process', Zend_Log::INFO);
    foreach ($this->_getBankFiles() as $bankFile) {
        $bankData = $this->_processBankFile($bankFile);
        $this->getLogger()->log('Processing ' . $bankData->transactionId, Zend_Log::DEBUG);
        /** @var Contact_Model_Contact $contact */
        $contact = $this->getMapper('Contact_Model_Mapper_Contact')
            ->findContactByBankAccount($bankData->transactionAccount);
        if (null !== $contact) {
            $this->getLogger()->log(sprintf('Found contact "%s" for bank account %s',
                $contact->getName(),$bankData->transactionAccount
            ), Zend_Log::DEBUG);
            $data = array (
                'amount' => $bankData->transactionAmount,
                'payment_date' => $bankData->transactionDate
            );
            $this->getMapper('Invoice_Model_Mapper_Payments')
                ->updatePayment($data, array ('contact_id = ?' => $contact->getContactId()));
            $this->_moveBankFile($bankFile,
                $this->getPath() . DIRECTORY_SEPARATOR . self::PROCESS_SUCCEEDED
            );
        } else {
            $this->getLogger()->log(sprintf(
                'Could not match bankaccount "%s" with a contact',
                $bankData->transactionAccount
            ), Zend_Log::WARN);
            $this->_moveBankFile($bankFile,
                $this->getPath() . DIRECTORY_SEPARATOR . self::PROCESS_FAILED
            );
        }
    }
}
102

class Payments_Service_As400Test extends PHPUnitFrameworkTestCase
{
    public function testProcessingBankPayments()
    {
        $contact = $this->getMockBuilder(Contact_Model_Contact::class)
            ->setMethods(['getContactId', 'getName'])
            ->getMock();
        $contact->expects($this->any())
            ->method('getContactId')
            ->will($this->returnValue(1));
            ->method('getName')
            ->will($this->returnValue('Foo Bar'));
        $contactMapper = $this->getMockBuilder(Contact_Model_Mapper_Contact::class)
            ->setMethods(['findContactByBankAccount'])
            ->getMock();
        $contactMapper->expects($this->any())
            ->method('findContactByBankAccount')
            ->will($this->returnValue($contact));
        $paymentsMapper = $this->getMockBuilder(Invoice_Model_Mapper_Payments::class)
            ->setMethods(['updatePayment'])
            ->getMock();
        $logMock = new Zend_Log_Writer_Mock();
        $logger = new Zend_Log();
        $logger->setWriter($logMock);
        $logger->setPriority(Zend_Log::DEBUG);
        $as400 = new Payments_Service_As400();
        $as400->addMapper($contactMapper, Contact_Model_Mapper_Contact::class)
            ->addMapper($paymentsMapper, Invoice_Model_Mapper_Payments::class)
            ->setPath(__DIR__ . DIRECTORY_SEPARATOR . '_files')
            ->setLogger($logger);
        $as400->processBankPayments();
        $this->assertCount(3, $logMock->events);
        $this->assertEquals('Processing 401341345', $logMock->events[1]);
        $this->assertEquals(
            'Found contact "Foo Bar" for bank account BE93522511513933',
            $logMock->events[2]
        );
    }
}
104

Let’s focus on mocks ﬁrst
$contact = $this->getMockBuilder(Contact_Model_Contact::class)
    ->setMethods(['getContactId', 'getName'])
    ->getMock();
    ->method('getContactId')
    ->will($this->returnValue(1));
    ->method('getName')
    ->will($this->returnValue('Foo Bar'));
$contactMapper = $this->getMockBuilder(Contact_Model_Mapper_Contact::class)
    ->setMethods(['findContactByBankAccount'])
    ->getMock();
$contactMapper->expects($this->any())
    ->method('findContactByBankAccount')
    ->will($this->returnValue($contact));
$paymentsMapper = $this->getMockBuilder(Invoice_Model_Mapper_Payments::class)
    ->setMethods(['updatePayment'])
    ->getMock();
105

Write the log mock
$logMock = new Zend_Log_Writer_Mock();
$logger = new Zend_Log();
$logger->setWriter($logMock);
$logger->setPriority(Zend_Log::DEBUG);
$as400 = new Payments_Service_As400();
$as400->addMapper($contactMapper, Contact_Model_Mapper_Contact::class)
    ->addMapper($paymentsMapper, Invoice_Model_Mapper_Payments::class)
    ->setPath(__DIR__ . DIRECTORY_SEPARATOR . '_files')
    ->setLogger($logger);
$as400->processBankPayments();
$this->assertCount(3, $logMock->events);
$this->assertEquals('Processing 401341345', $logMock->events[1]);
$this->assertEquals(
    'Found contact "Foo Bar" for bank account BE93522511513933',
    $logMock->events[2]
);
106

Exercise
Check out the web app
git checkout legacy-0.2
Go and check out branch legacy-0.2 where you
will ﬁnd the example test case.
10 minutes

Privates Exposed
109
http://www.slashgear.com/former-tsa-agent-admits-we-knew-full-body-scanners-didnt-work-31315288/

Direct access forbidden?!?
<?php
defined("_VALID_ACCESS") || die('Direct access forbidden');
/**
* This class provides dependency requirements
* @package epesi-base
* @subpackage module
*/
class Dependency {
    private $module_name;
    private $version_min;
    private $version_max;
    private $compare_max;
    private function __construct(
$module_name, $version_min, $version_max, $version_max_is_ok = true) {
        $this->module_name = $module_name;
        $this->version_min = $version_min;
        $this->version_max = $version_max;
        $this->compare_max = $version_max_is_ok ? '<=' : '<';
    }
    /** ... */
}
110

Don’t touch my junk!
111
https://www.ﬂickr.com/photos/caseymultimedia/5412293730

House of Reﬂection
https://www.ﬂickr.com/photos/tabor-roeder/8250770115

Let’s do this…
<?php
require_once 'include.php';
class DependencyTest extends PHPUnit_Framework_TestCase
{
    public function testConstructorSetsProperSettings()
    {
        require_once 'include/module_dependency.php';
        // We have a problem, the constructor is private!
    }
}
113

Using static method works too
$params = array (
    'moduleName' => 'Foo_Bar',
    'minVersion' => 0,
    'maxVersion' => 1,
    'maxOk' => true,
);
// We use a static method for this test
$dependency = Dependency::requires_range(
    $params['moduleName'],
    $params['minVersion'],
    $params['maxVersion'],
    $params['maxOk']
);
// We use reflection to see if properties are set correctly
$reflectionClass = new ReflectionClass('Dependency');
114

Asserting private properties
// Let's retrieve the private properties
$moduleName = $reflectionClass->getProperty('module_name');
$moduleName->setAccessible(true);
$minVersion = $reflectionClass->getProperty('version_min');
$minVersion->setAccessible(true);
$maxVersion = $reflectionClass->getProperty('version_max');
$maxVersion->setAccessible(true);
$maxOk = $reflectionClass->getProperty('compare_max');
$maxOk->setAccessible(true);
// Let's assert
$this->assertEquals($params['moduleName'], $moduleName->getValue($dependency),
    'Expected value does not match the value set’);
$this->assertEquals($params['minVersion'], $minVersion->getValue($dependency),
$this->assertEquals($params['maxVersion'], $maxVersion->getValue($dependency),
$this->assertEquals('<=', $maxOk->getValue($dependency),
    'Expected value does not match the value set');
115

Agenda
117
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

PHPUnit requires basic PHP!
Sometimes the challenge lies within PHP instead of direct PHPUnit
Testing is simple, coding is hard!
Testing is all about asserting that an actual process matches an expected result,
so make sure you cover your expectations and test against those expectations
PHP functionality you need to know:
Reﬂection
Streams
System and PHP executions (e.g. “eval”, “passthru”, …)
118

If you don’t know the destination…
Start testing with what you know
Work your way up
119

“But my code is too crappy…”
120

For “untestable” code
Write out the functionality in tests
Create a class providing this functionality (service, model, …)
Slowly move your existing code over to use the “cleaner” code
Bonus: you’ve got it already tested
121

Agenda
122
Introduction
TDD from scratch
TDD with legacy app
Additional tips
Recap

Everything is testable!
Not always easy, but always possible

Write your tests ﬁrst
Write your code based on your tests

Use code coverage as guide
It shows your progress through the code

Be creative!
Sometimes PHP can help out

Let your tests drive your code

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