introductiontophpunitandbestpractices-090721111610-phpapp02

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Introduction to PHPUnit & Best Practices

Sebastian Bergmann

July 20th 2009



Who I am

Sebastian Bergmann Involved in the PHP

project since 2000

Creator of PHPUnit Co-Founder and

Principal Consultantwith thePHP.cc

http://sebastian-bergmann.de/

http://www.phpunit.de/

http://thephp.cc/

http://thephp.cc/

http://www.phpunit.de/

http://sebastian-bergmann.de/



The Bank Account ExampleBankAccount.php<?php

class BankAccount {protected $balance = 0;

public function getBalance() {return $this->balance;

}

protected function setBalance($balance) {

if ($balance >= 0) { $this->balance = $balance;

} else {throw new RuntimeException;

}}

public function depositMoney($balance) { $this->setBalance($this->getBalance() + $balance);

}

public function withdrawMoney($balance) { $this->setBalance($this->getBalance() - $balance);

}}

?>



The Bank Account Example

<?phprequire_once 'BankAccount.php';

class BankAccountTest extends PHPUnit_Framework_TestCase {

}

BankAccountTest.php



The Bank Account ExampleBankAccountTest.php<?phprequire_once 'BankAccount.php';

class BankAccountTest extends PHPUnit_Framework_TestCase {public function testBalanceIsInitiallyZero() {

}

}





$ba = new BankAccount; $this->assertEquals(0, $ba->getBalance());

return $ba;}

}





$ba = new BankAccount;$this->assertEquals(0, $ba->getBalance());

return $ba;}

/*** @depends testBalanceIsInitiallyZero* @expectedException RuntimeException*/public function testBalanceCannotBecomeNegative(BankAccount $ba) {

$ba->withdrawMoney(1);}

}





$ba = new BankAccount;$this->assertEquals(0, $ba->getBalance());

return $ba;}

/*** @depends testBalanceIsInitiallyZero* @expectedException RuntimeException*/public function testBalanceCannotBecomeNegative(BankAccount $ba) {

$ba->withdrawMoney(1);}

/*** @depends testBalanceIsInitiallyZero* @expectedException RuntimeException*/public function testBalanceCannotBecomeNegative2(BankAccount $ba) {

$ba->depositMoney(-1);}

// ...}




class BankAccountTest extends PHPUnit_Framework_TestCase {// ...

/*** @depends testBalanceIsInitiallyZero*/public function testDepositingMoneyWorks(BankAccount $ba) {

$ba->depositMoney(1); $this->assertEquals(1, $ba->getBalance());

return $ba;}

}




class BankAccountTest extends PHPUnit_Framework_TestCase {// ...

/*** @depends testBalanceIsInitiallyZero*/public function testDepositingMoneyWorks(BankAccount $ba) {

$ba->depositMoney(1);$this->assertEquals(1, $ba->getBalance());

return $ba;}

/*** @depends testDepositingMoneyWorks*/

public function testWithdrawingMoneyWorks(BankAccount $ba) { $ba->withdrawMoney(1); $this->assertEquals(0, $ba->getBalance());

}}



The Bank Account ExampleRunning tests

sb@ubuntu ~ % phpunit BankAccountTest

PHPUnit 3.4.0 by Sebastian Bergmann.

.....

Time: 0 seconds

OK (5 tests, 5 assertions)



The Bank Account Example

<?phpclass BankAccount {

protected $balance = 1;

public function getBalance() {return $this->balance;

}

protected function setBalance($balance) {

if ($balance >= 0) {$this->balance = $balance;

} else {throw new RuntimeException;

}}

public function depositMoney($balance) {$this->setBalance($this->getBalance() + $balance);

}

public function withdrawMoney($balance) {$this->setBalance($this->getBalance() - $balance);

}}

?>

BankAccount.php




sb@ubuntu ~ % phpunit BankAccountTest


FSSSS

Time: 0 seconds

There was 1 failure:

1) BankAccountTest::testBalanceIsInitiallyZeroFailed asserting that <integer:1> matches expected <integer:0>./home/sb/BankAccountTest.php:7

FAILURES!Tests: 1, Assertions: 1, Failures: 1, Skipped: 4.




sb@ubuntu ~ % phpunit --verbose BankAccountTestPHPUnit 3.4.0 by Sebastian Bergmann.

FSSSS

Time: 0 seconds


1) BankAccountTest::testBalanceIsInitiallyZeroFailed asserting that <integer:1> matches expected <integer:0>.

/home/sb/BankAccountTest.php:7

There were 4 skipped tests:

1) BankAccountTest::testBalanceCannotBecomeNegativeThis test depends on "BankAccountTest::testBalanceIsInitiallyZero" to pass.

2) BankAccountTest::testBalanceCannotBecomeNegative2This test depends on "BankAccountTest::testBalanceIsInitiallyZero" to pass.

3) BankAccountTest::testDepositingMoneyWorksThis test depends on "BankAccountTest::testBalanceIsInitiallyZero" to pass.

4) BankAccountTest::testWithdrawingMoneyWorksThis test depends on "BankAccountTest::testDepositingMoneyWorks" to pass.

FAILURES!Tests: 1, Assertions: 1, Failures: 1, Skipped: 4.



The Bank Account ExampleCode Coverage

sb@ubuntu ~ % phpunit --coverage-html /tmp/report BankAccountTest


.....

Time: 0 seconds

OK (5 tests, 5 assertions)

Generating code coverage report, this may take a moment.



”The secret in testing isin writing testable code”

Miš

ko Hevery



Untestable Code

Most people say Make things private

Use final keyword

Write long methods ...

Real issues Mix new with logic

Look for things

Work in constructor Singletons

Global state

Static methods

This slide contains material by Miško Hevery



Untestable Code

<?php

class Document {private $html;

public function __construct($url) { $client = new HttpClient; $this->html = $client->get($url);

}}

Mixing object graph

construction with work

Doing work in theconstructor


Object Graph Construction Issues



<?php


public function __construct(HttpClient $client, $url) { $this->html = $client->get($url);

}

}

Doing work in theconstructor


Untestable CodeObject Graph Construction Issues



<?php

class DocumentFactory {public function __construct(HttpClient $client) { $this->client = $client;

}

public function build($url) {

return new Document($this->client->get($url));}}


Untestable CodeDecouple object graph construction from other work



<?php

class DocumentFactory {public function __construct(HttpClient $client) {$this->client = $client;

}

public function build($url) {

return new Document($this->client->get($url));}}


public function __construct($html) { $this->html = $html;

}}


Untestable CodeDecouple object graph construction from other work



Untestable CodeGlobal State

Global variables Static variables in classes

Static variables in functions and methods

Persistent Data Database

Filesystem

Distributed Data memcached

bl d



Untestable CodeGlobal Variables in PHP

A variable $foo declared in the global scopeis stored in $GLOBALS['foo'].

$GLOBALS is a so-called superglobal.

Superglobals are built-in variables that areavailable in all scopes.

$GLOBALS['foo'] can be used to access theglobal variable $foo in the scope of a

function or method global $foo; can be used to create a local

variable with a reference to the globalvariable.

bl d



Untestable CodeGlobal Variables in PHP

$GLOBALS = array( 'GLOBALS' => &$GLOBALS, '_ENV' => array(), '_POST' => array(),

'_GET' => array(), '_COOKIE' => array(), '_SERVER' => array(), '_FILES' => array(),

'_REQUEST' => array());

bl d



Untestable CodePHPUnit and Global Variables

Default Behaviour Backup $GLOBALS before the execution of a test

Run the test

Restore $GLOBALS after the execution of a test

$backupGlobals = FALSE Do not backup and restore $GLOBALS

$backupGlobalsBlacklist = array() Backup and restore $GLOBALS but not the

variables listed in the array

bl C d



Untestable CodePHPUnit and Static Attributes

Default Behaviour

Backup static attributes of user-defined classes before theexecution of a test

Run the test

Restore static attributes of user-defined classes after theexecution of a test

$backupStaticAttributes = FALSE

Do not backup and restore static attributes of user-

defined classes

$backupStaticAttributesBlacklist = array()

Backup and restore static attributes of user-defined

classes but not the variables listed in the array

U bl C d




Untestable CodeHidden Global State

Loaded source files Loaded classes and functions

Sent HTTP headers

new DateTime()

time()

mktime()

rand()

T bl C d



Testable Code

Few Branches More branches increase complexity

Higher complexity leads to more errors

Higher complexity makes testing harder

Few Dependencies

Improved isolation for defect localization Should be injectable to be replacable by

test-specific equivalents

Selected Aspects of Testability

PHPU i B P i



PHPUnit Best PracticesUse an XML Configuration File

<?xml version="1.0" encoding="UTF-8"?>

<phpunit backupGlobals="false" backupStaticAttributes="false" syntaxCheck="false"></phpunit>

PHPU i B P i





<phpunit backupGlobals="false"backupStaticAttributes="false"syntaxCheck="false">

<testsuites><testsuite name="My Test Suite"><directory>path/to/dir</directory>

</testsuite></testsuites>

</phpunit>

PHPU i B P i






<php><const name="foo" value="bar"/><var name="foo" value="bar"/><ini name="foo" value="bar"/>

</php></phpunit>

PHPU i B P i



PHPUnit Best PracticesUse Code Coverage Whitelisting



<filter><whitelist addUncoveredFilesFromWhitelist="true"><directory suffix=".php">path/to/dir</directory>

</whitelist></filter>

</phpunit>

PHPU it B t P ti



PHPUnit Best PracticesMake the Code Coverage information more meaningful

/**

* @covers Object_Freezer::freeze*/public function testFreezingAnObjectWorks(){ $this->assertEquals(

array( /* ... */ ), $this->freezer->freeze(new A(1, 2, 3))

);}

PHPU it B t P ti



PHPUnit Best PracticesExploit dependencies between tests

/**

* @covers Object_Freezer::freeze* @covers Object_Freezer::thaw* @depends testFreezingAnObjectWorks*/public function testFreezingAndThawingAnObjectWorks(){ $object = new A(1, 2, 3);

$this->assertEquals( $object, $this->freezer->thaw(

$this->freezer->freeze($object))

);}

PHPU it B t P ti



Decouple test code from complex / large sets of test data

<?phpclass DataTest extends PHPUnit_Framework_TestCase{ /**

* @dataProvider providerMethod*/public function testAdd($a, $b, $c){

$this->assertEquals($c, $a + $b);}

public function providerMethod(){

return array(array(0, 0, 0),

array(0, 1, 1),array(1, 1, 3),array(1, 0, 1)

);}

}

PHPUnit Best Practices

PHPU it B t P ti



PHPUnit Best Practices

sb@ubuntu ~ % phpunit DataTestPHPUnit 3.4.0 by Sebastian Bergmann.

..F.

Time: 0 seconds


1) testAdd(DataTest) with data (1, 1, 3)Failed asserting that <integer:2> matches expected value <integer:3>./home/sb/DataTest.php:19

FAILURES!Tests: 4, Assertions: 4, Failures: 1.

Decouple test code from complex / large sets of test data

PHPU it B st Pr ti s



PHPUnit Best PracticesWrite code that allows you to disable PHPUnit features

Syntax Check Backup/Restore of global variables

Backup/Restore of static attributes

The End



The End

Thank you for your interest!

These slides will be posted on

http://slideshare.net/sebastian_bergmann

License





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●

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