Unit Testing
First Steps
Jakob Heuser http://www.slideshare.net/jakobo

Who?
• 10 years in the industry
• Academic Skills
Achievement Program
• Homeland Security
Digital Library
• Gaia Online
• LinkedIn

Who?

Who?

Who?

Who?

Our Goal
• Break down testing myths
• Grasp testing (the concept)
• See a few tests
• Walk out wanting to write some tests

Covering
• Intro
• Simple Tests
• Frameworks
• Darts
• Advocacy
This is some code
This is a passing test
This is a failing test

Unit Testing Is
• Easier than you think
• Probably harder than it should be
• An idea not a software package
• (though there is software for it)

Unit
• Smallest testable part of an application

Unit
• Smallest testable part of an application
• Function (or)

Unit
• Smallest testable part of an application
• Function (or)
• Public method (or)

Unit
• Smallest testable part of an application
• Function (or)
• Public method (or)
• Included file

Unit Testing Concept
• Given X and Y, Z should happen
• Make changes to your code
• Given X and Y, Z should still happen

Testing Requirements not the Code

Testing Requirements?
• Requirements define code
• Serve as documentation for the code
alongside the code itself

A Very Basic Test
<?PHP
function addLineBreaks($in_string) {
$in_string = str_replace("n", "n<br/>");
return $in_string;
}

A Very Basic Test
<?PHP
function addLineBreaks($in_string) {
$in_string = str_replace("n", "n<br/>");
return $in_string;
}
<?PHP
$str = "This isna test";
echo "nn===n";
echo addLineBreaks($str);
echo "n===nn";

Visual Inspection
• This is a “test”
• Quick to write and verify

I Can’t Do That For EVERYTHING!

What If...
• we had hundreds of tests
• we didn’t have time to visually inspect
output
• we could describe what we want
programatically

Solutions?

Testing Frameworks
• Condense our “testing” process
• Tell us what went wrong, and why
• Automated

Testing Frameworks
• SnapTest (snaptest.net)
• PHPUnit (phpunit.de)
• SimpleTest (simpletest.org)
• Testilence (testilence.org)
• (some MVC frameworks have testing)

Testing Frameworks
• Every framework has different goals
• Find what’s right for you and your project

SnapTest (5)

SnapTest
• Simplify the testing process
• Lower barrier to entry
(at cost of doing it “all”)
• Run in any environment including via web

PHPUnit (4, 5)

PHPUnit
• Can test pretty much anything
• Most established project
• Test coverage analysis with XDebug

SimpleTest (4, 5)

SimpleTest
• Web test runner support
• Very small footprint
• Simulate browser events

Testilence (5)

Testilence
• PHP 5 targeted
• C shell runner “tence”

So Which One?
• Examples tonight use SnapTest
• Focus on the theory

The Game of Darts

The Rules of Darts
• Start at 501 points
• Goal is to reach 0 points
• 3 throws results in a score
• Must finish on 0 exactly

Our Code
<?PHP
class DartsGame { Score starts
protected $score;
at 501
public function __construct() {
$this->score = 501;
}
public function throwDart($score) {
if ($this->score - $score < 0) {
return $this->score;
}
$this->score = $this->score - $score;
return $this->score;
}
public function getScore() {
return $this->score;
}
}

Our Code
<?PHP
class DartsGame {
protected $score;
public function __construct() {
$this->score = 501;
}
Throw a
public function throwDart($score) {
if ($this->score - $score < 0) { dart
return $this->score;
}
$this->score = $this->score - $score;
return $this->score;
}
public function getScore() {
return $this->score;
}
}

Our Code
<?PHP
class DartsGame {
protected $score;
public function __construct() {
$this->score = 501;
}
public function throwDart($score) {
if ($this->score - $score < 0) {
return $this->score;
}
$this->score = $this->score - $score; Save new
}
return $this->score;
score
public function getScore() {
return $this->score;
}
}

Our Code
<?PHP
class DartsGame {
protected $score;
public function __construct() {
$this->score = 501;
}
public function throwDart($score) {
if ($this->score - $score < 0) {
return $this->score;
}
$this->score = $this->score - $score;
return $this->score;
}
public function getScore() {
}
return $this->score; Get the
} current score

Our First Test
• A new game
• Score should be 501

Our First Test
<?PHP
require_once 'basedarts.php';
class New_Game_No_Throws extends Snap_UnitTestCase {
public function setUp() {
$this->Darts = new DartsGame();
}
public function tearDown() {
unset($this->Darts);
}
public function testScoreIsFiveHundredOne() {
return $this->assertEqual($this->Darts->getScore(), 501);
}
}

Our Results
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
.
______________________________________________________________________
Total Cases: 1
Total Tests: 1
Total Pass: 1
Total Defects: 0
Total Failures: 0
Total Skips: 0
Total Todo: 0

Our Second Test
• A new game
• Throw 10, 0, 0
• Score should be 491

Our Test
<?PHP
require_once 'basedarts.php';
class Throw_Ten_Zero_Zero_Test extends Snap_UnitTestCase { Throw some
public function setUp() { darts
$this->Darts = new DartsGame();
$this->Darts->throwDart(10);
$this->Darts->throwDart(0);
$this->Darts->throwDart(0);
}
public function tearDown() {
unset($this->Darts);
}
public function testScoreIsFourNinteyOne() {
return $this->assertEqual($this->Darts->getScore(), 491);
}
}

Our Test
<?PHP
require_once 'basedarts.php';
class Throw_Ten_Zero_Zero_Test extends Snap_UnitTestCase {
public function setUp() {
$this->Darts = new DartsGame();
$this->Darts->throwDart(10);
$this->Darts->throwDart(0);
$this->Darts->throwDart(0);
Reset dart game
} when done
public function tearDown() {
unset($this->Darts);
}
public function testScoreIsFourNinteyOne() {
return $this->assertEqual($this->Darts->getScore(), 491);
}
}

Our Test
<?PHP
require_once 'basedarts.php';
class Throw_Ten_Zero_Zero_Test extends Snap_UnitTestCase {
public function setUp() {
$this->Darts = new DartsGame();
$this->Darts->throwDart(10);
$this->Darts->throwDart(0);
$this->Darts->throwDart(0);
}
public function tearDown() {
unset($this->Darts);
}
The Test
public function testScoreIsFourNinteyOne() {
return $this->assertEqual($this->Darts->getScore(), 491);
}
}

Our Results
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
..
______________________________________________________________________
Total Cases: 2
Total Tests: 2
Total Pass: 2
Total Defects: 0
Total Failures: 0
Total Skips: 0
Total Todo: 0
Okay, is this working?

Sanity Check
<?PHP
class DartsGame {
protected $score;
public function __construct() {
$this->score = 501;
} Broken in a very
public function throwDart($score) { obvious way
if ($this->score - $score < 0) {
return $this->score;
}
$this->score = 0;
return $this->score;
}
public function getScore() {
return $this->score;
}
}

Predictable Failure
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
.F
Equal (==) assertion failed. [int(491) != int(0)]
in method: testScoreIsFourNinteyOne
in class: Throw_Ten_Zero_Zero_Test
in file: /Users/jakobo/Dropbox/2009-06-18 unittesting/resources/
basedarts.stest.php
______________________________________________________________________
Total Cases: 2
Total Tests: 2
Total Pass: 1
Total Defects: 0
Total Failures: 1
Total Skips: 0
Total Todo: 0

Back to our Rules
• Start at 501 points
• Goal is to reach 0 points
• 3 throws results in a score
• Must finish on 0 exactly

The Next Test
<?PHP
require_once 'basedarts.php';
class Throw_Last_Set_Over_501_Test extends Snap_UnitTestCase {
public function setUp() {
$this->Darts = new DartsGame();
$this->Darts->throwDart(50);
// down by 450 (51 left, next block shouldn’t score)
$this->Darts->throwDart(50);
$this->Darts->throwDart(50);
$this->Darts->throwDart(1);
}
// ...
public function testScoreIsFiftyOne() {
return $this->assertEqual($this->Darts->getScore(), 51);
}
}

Huh...
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
.F.
Equal (==) assertion failed. [int(51) != int(0)]
in method: testScoreIsFiftyOne
in class: Throw_Last_Set_Over_501_Test
in file: /Users/jakobo/Dropbox/2009-06-18 unittesting/resources/
basedarts_overage.stest.php
______________________________________________________________________
Total Cases: 3
Total Tests: 3
Total Pass: 2
Total Defects: 0
Total Failures: 1
Total Skips: 0
Total Todo: 0

When Code Doesn’t Match Requirements

A Bug Found
<?PHP
class DartsGame {
protected $score;
public function __construct() {
$this->score = 501;
}
public function throwDart($score) {
if ($this->score - $score < 0) {
return $this->score; “3 throws results
}
in a score”
$this->score = $this->score - $score;
return $this->score;
}
public function getScore() {
return $this->score;
}
}

Solving the Bug
• Keep track of “turns” and only score every
3 throws

Dealing With the Bug
<?PHP
class DartsGame {
protected $score;
protected $throws;
public function __construct() {
$this->score = 501;
$this->throws = array();
}
public function throwDart($score) { Address the Bug
$this->throws[] = $score;
if (count($this->throws) < 3) {
return $this->score;
}
$score = $this->throws[0] + $this->throws[1] + $this->throws[2];
$this->throws = array();
// ...
}

Fixed!
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
...
______________________________________________________________________
Total Cases: 3
Total Tests: 3
Total Pass: 3
Total Defects: 0
Total Failures: 0
Total Skips: 0
Total Todo: 0

“What If” Thinking
(Rules say: I was supposed to throw in 3’s)
If I don’t throwDart() in a multiple of 3,
what happens?

“What If” Thinking
• “Well then, I’d expect it to throw an
exception”
• Update the requirements, then add a test

“TDD” or “Test First”
<?PHP
require_once 'basedarts_throws.php';
class Throw_Non_Multiple_Of_Three_Test extends Snap_UnitTestCase {
public function setUp() {
$this->Darts = new DartsGame();
$this->Darts->throwDart(50);
$this->Darts->throwDart(50);
}
public function tearDown() {
unset($this->Darts);
} “I expect _____
to happen”
public function testGetScoreThrowsException() {
$this->willThrow("Exception");
$this->Darts->getScore();
$this->assertFalse(true, 'An exception was not thrown');
}
}

Of Course it Fails
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
...F
FALSE assertion got TRUE. [bool(true) !== bool(false)] with user message: An
exception was not thrown
in method: testGetScoreThrowsException
in class: Throw_Non_Multiple_Of_Three_Test
in file: /Users/jakobo/Dropbox/2009-06-18 unittesting/resources/
basedarts_multiple.stest.php
______________________________________________________________________
Total Cases: 4
Total Tests: 4
Total Pass: 3
Total Defects: 0
Total Failures: 1
Total Skips: 0
Total Todo: 0
We should write that part...

Write in Solution
<?PHP
class DartsGame {
// ...
public function getScore() {
if (count($this->throws)) {
throw new Exception('Darts must be thrown in multiples of 3');
}
return $this->score;
}
}
Meeting our
requirement

Our Results
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
....
______________________________________________________________________
Total Cases: 4
Total Tests: 4
Total Pass: 4
Total Defects: 0
Total Failures: 0
Total Skips: 0
Total Todo: 0

You Just Learned “TDD”

Refactoring
• Change the internals freely
• “throws” array
• way score is tallied
• Verify your “rules” are still adhered to

Refactoring
<?PHP
class DartsGame {
// ...
public function throwDart($score) {
$this->throws[] = $score;
if (count($this->throws) < 3) {
return $this->score;
}
$throws = $this->throws;
$this->throws = array();
return $this->scoreTrio($throws[0], $throws[1], $throws[2]);
}
// ...
protected function scoreTrio($throw_one, $throw_two, $throw_three) {
$score = $throw_one + $throw_two + $throw_three;
if ($this->score - $score < 0) {
return $this->score;

Refactoring
// ...
protected function scoreTrio($throw_one, $throw_two, $throw_three) {
$score = $throw_one + $throw_two + $throw_three;
if ($this->score - $score < 0) {
return $this->score;
}
$this->score = $this->score - $score;
return $this->score;
}
}

And Rerun Tests
jakobo@Hikaru ~/Dropbox/2009-06-18 unittesting/resources> snaptest.sh ./
....
______________________________________________________________________
Total Cases: 4
Total Tests: 4
Total Pass: 4
Total Defects: 0
Total Failures: 0
Total Skips: 0
Total Todo: 0

Advocacy / Recap
• Testing is a good thing
• Testing is easy
• We’re testing requirements, not code

Advocacy / Recap
• There are frameworks for testing
• Tests can be automated

Advocacy / Recap
• You can test new and established code
• You can refactor code safely

Next Steps
• Download a framework
• Check your requirements
• Write some tests
• Be happier!

Unit Testing
First Steps
Jakob Heuser http://www.slideshare.net/jakobo

Appendix
http://www.flickr.com/photos/ratterrell/125200561
http://www.flickr.com/photos/wili/214316968
http://www.flickr.com/photos/mommamia/210433527
http://www.flickr.com/photos/syldavia/206163304
http://www.flickr.com/photos/mr_o/3606222762/

Appendix
http://www.flickr.com/photos/frield/95509221/
http://flickr.com/photos/deerwooduk/579761138
http://www.flickr.com/photos/brom/1329688851