Unit testing

Unit TestingBy David Haskins

bool underAttack = false;

underAttack = detectEvents();

//do some other stuff

if(underAttack = true) {launchNuclearMissles();

} else {alert(“false alarm!”);

}

Why Test?

• Sometimes we make mistakes in our code

Why Test?


• Sometimes we forget to finish parts of our code because we get interrupted, and then we never come back and finish

Why Test?


• Sometimes we forget to finish parts of our code because we get interrupted, and then we never come back and finish

• //TODO: add another reason

Testing vs. Debugging

Testing: detecting errors

Debugging: diagnose and repair detected errors

Types of testing

regression tests

functional tests

acceptance tests

integration tests

load/stress tests

security tests

unit tests

Unit Testing

Unit Testing: the execution of [code] that has been written by a single programmer or team of programmers, which is tested in isolation from the more complete system.

- Code Complete 2nd ed.

How we end up testing stuff

class User{

public function __construct($userName){

//do stuff

}

public function checkPassword($password){

//do stuff

}

public function setLogIn(){

//do stuff

}

}


$u = new User(‘[email protected]’);

//test to fail

$u->checkPassword(‘bad_password’);

//test to succeed

$u->checkPassword(‘s3kr3t_p@sswd’);


$u = new User(‘[email protected]’);

//test to fail

if($u->checkPassword(‘bad_password’) === false){

echo ‘successfully rejected’;

}

//test to succeed

if($u->checkPassword(‘s3kr3t_p@sswd’) === true){

echo ‘successfully accepted’;

}

What do we do with this information?


We delete it!!!


We delete it!!!

(or, at best, we comment it out)

PHPUnit

• a framework for unit testing PHP

• excellent documentation at http://phpunit.de

• easy to setup

http://phpunit.de/

http://phpunit.de/

Installing PHPUnit

• Pear

• Composer (preferred method)

Installing PHPUnit

pear config-set audto_discover 1

pear install pear.phpunit.de/PHPUnit

Installing PHPUnit

Composer can be used to download and install “dependencies”(other libraries and such).

download composer:

curl -s http://getcomposer.org/installer | php

Installing PHPUnit

create a file named composer.json containing:

{

“require-dev”: {

“phpunit/phpunit”: “3.7.4”

}

}

Installing PHPUnit

run:

./composer.phar update

(a .phar file is a “PHP Archive” file.)

Installing PHPUnit

create a file named phpunit.xml containing:

<?xml version="1.0" encoding="UTF-8"?><phpunit colors="true"> <testsuites> <testsuite name="Application Test Suite"> <directory>./phpUnitTutorial/Test/</directory> </testsuite> </testsuites></phpunit>

Running PHPUnit

./vendor/bin/phpunit

A simple PHPUnit test

class myTest extends PHPUnitTest_Framework_TestCase {

}


public function someSimpleTest(){

}

}



$myVar = true;

$this->assertTrue($myVar);

}

}



$myVar = true;

$this->assertTrue($myVar);

}

public function anotherSimpleTest(){

$myVar = false;

$this->assertTrue($myvar); //fails

}

}

PHPUnit offers:

assertTrue();

assertFalse();

assertEquals();

assertArrayHasKey();

assertStringEndsWith();

...and many more!

The next few examples are

from Juan Treminio’s tutorial:

https://jtreminio.com/2013/03


The phrase “slugify” means to change

something like this:

The quick BROWN fox @ noon

into this:

the-quick-brown-fox-noon

<?phpclass URL{ public function sluggify($string, $separator = '-', $maxLength = 96) { $title = iconv('UTF-8', 'ASCII//TRANSLIT', $string); $title = preg_replace("%[^-/+|\w ]%", '', $title); $title = strtolower(trim(substr($title, 0, $maxLength), '-')); $title = preg_replace("/[\/_|+ -]+/", $separator, $title);

return $title; }

}

Let’s write a test for it!

namespace phpUnitTutorial\Test;use phpUnitTutorial\URL;class URLTest extends \PHPUnit_Framework_TestCase{

}

namespace phpUnitTutorial\Test;use phpUnitTutorial\URL;class URLTest extends \PHPUnit_Framework_TestCase{ public function testSluggifyReturnsSluggifiedString() { $originalString = 'This string will be sluggified'; $expectedResult = 'this-string-will-be-sluggified';

}

}


$url = new URL();

$result = $url->sluggify($originalString);

}

}


$url = new URL();


$this->assertEquals($expectedResult, $result); }

}

We have a unit test!

{run example}

Other tests we can add

public function testSluggifyReturnsExpectedForStringsContainingNumbers() { $originalString = 'This1 string2 will3 be 44 sluggified10'; $expectedResult = 'this1-string2-will3-be-44-sluggified10';

$url = new URL();




public function testSluggifyReturnsExpectedForStringsContainingSpecialCharacters() { $originalString = 'This! @string#$ %$will ()be "sluggified'; $expectedResult = 'this-string-will-be-sluggified';

$url = new URL();




public function testSluggifyReturnsExpectedForStringsContainingNonEnglishCharacters() { $originalString = "Tänk efter nu – förr'n vi föser dig bort"; $expectedResult = 'tank-efter-nu-forrn-vi-foser-dig-bort';

$url = new URL();




public function testSluggifyReturnsExpectedForEmptyStrings() { $originalString = ''; $expectedResult = '';

$url = new URL();



{run example without comments}

That’s neat, but it seems we are writing the same code over and over.


We can use the “dataProvider annotation.”


We can use the “dataProvider annotation.”

Annotations are described in docblocks (comments) of methods.

class URLTest extends \PHPUnit_Framework_TestCase{ /** * @dataProvider providerTestSluggifyReturnsSluggifiedString */ public function testSluggifyReturnsSluggifiedString($originalString, $expectedResult) {

//do our assertion here }

public function providerTestSluggifyReturnsSluggifiedString() {

//return an array of arrays which contains our data }}

class URLTest extends \PHPUnit_Framework_TestCase{ /** * @dataProvider providerTestSluggifyReturnsSluggifiedString */ public function testSluggifyReturnsSluggifiedString($originalString, $expectedResult) { $url = new URL();



public function providerTestSluggifyReturnsSluggifiedString() { return array( array('This string will be sluggified', 'this-string-will-be-sluggified'), array('THIS STRING WILL BE SLUGGIFIED', 'this-string-will-be-sluggified'), array('This1 string2 will3 be 44 sluggified10', 'this1-string2-will3-be-44-sluggified10'), array('This! @string#$ %$will ()be "sluggified', 'this-string-will-be-sluggified'), array("Tänk efter nu – förr'n vi föser dig bort", 'tank-efter-nu-forrn-vi-foser-dig-bort'), array('', ''), ); }}

I haven’t been honest here

URL::Sluggify() was deceptively simple it; had no dependencies.

When you're doing testing like this, you're focusing on one element of the software at a time -hence the common term unit testing. The problem is that to make a single unit work, you often need other units...

- Martin Fowlerhttp://martinfowler.com/articles/mocksArentStubs.html

http://martinfowler.com/articles/mocksArentStubs.html

What happens when we depend on other stuff (databases, other objects, etc.)?

setUp() and tearDown()

class FoobarTest extends PHPUnit_Framework_Testcase{

public function setUp(){

//do things before these tests run

// copy a production database into a test db

// instantiate objects

// define constants

}

public function tearDown(){

//do things after the tests run

// delete test db

}

}

But we still have problems

Databases can go down which could cause our tests to fail.

Instantiating objects can be slow which could make testing take forever (we want to be able to test often).

...and we want isolation!

“Mocks and stubs” to the rescue!

We may have to jump through some hoops, but we’ll get there!

Stubs//a method with stuff (implementation details irrelevant)

public function doSomething($param1, $param2){

mysql_connect("your.hostaddress.com", $param1, $param2) or

die(mysql_error());

mysql_select_db("address") or die(mysql_error());

!(isset($pagenum)) ? $pagenum = 1 : $pagenum=0;

$data = mysql_query("SELECT * FROM topsites") or die(mysql_error());

$rows = mysql_num_rows($data);

$page_rows = 4;

$last = ceil($rows/$page_rows);

$pagenum < 1 ? $pagenum=1 : $pagenum = $last;

$max = 'limit ' .($pagenum - 1) * $page_rows .',' .$page_rows;

return $max;

}

Stubs//a method with stuff (implementation details irrelevant)

public function StubDoSomething($param1, $param2){

return null;

}

Mock objects

Mock Objects: objects pre-programmed with expectations which form a specification of the calls they are expected to receive.

Mock objects

Let’s look at an example.

Mock objectsclass User{

public function __construct($id){

$this-> id = $id;

}

public function verifyUser(){

//validate against an LDAP server

}

public function getName(){

//get user name from the LDAP server

}

}

Mock objectsclass ForumPost{

public function deletePostsByUser($user){

$user_id = $user->getUserID();

$query = “delete from posts where userID = ? ”;

….//do stuff

}

//...other methods

}

require_once ‘User.php’;

require_once ‘ForumPost.php’;

class testForum extends PHPUnitTest_Framework_TestCase {

public function testUserPostDelete(){

$user = new User(7);

$userName = $user->getName();

$post = new ForumPost();

$rowsDeleted = $post->deletePostsByUser($user);

$message = “$rowsDeleted posts removed for $userName”;

$expectedMessage = “5 posts removed for David Haskins”;

$this->assertEquals($message,$expectedMessage);

}

}





$user = new User(7); //fails when LDAP server is down!







}

}





$user = $this->getMockBuilder(‘User’)

->setConstructorArgs(array(7))

->getMock();

$user->expects($this->once())

->method(‘getName’)

->will($this->returnValue(‘David Haskins’);







}

}

TDD

Test Driven Development is a method of developing code by writing the tests FIRST!

Git and unit tests

You can add client or server side “hooks” to git to run your unit tests and reject submissions that fail the unit tests.

http://www.masnun.com/2012/03/18/running-phpunit-on-git-hook.html

http://www.masnun.com/2012/03/18/running-phpunit-on-git-hook.html

Coverage report tool

./vendor/bin/phpunit --coverage-html coverage

bool underAttack = false;

underAttack = detectEvents();

//do some other stuff

if(underAttack = true) {launchNuclearMissles();

} else {alert(“false alarm!”);

}

Other Texts to Consider


http://phpunit.de


http://phpunit.de/

Unit testing

Education

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