TDD, a starting point...

TDD, a starting point
A PHP perspective...
Francesco Fullone, Ideato.it
ff AT ideato.it

Who am I

Francesco Fullone aka Fullo

- PHP developer since 1999
- President
- and Open Source Evangelist
- CEO @

- Nerd and geek

Developers are humans,
Humans are error-prone.

Software changes
and grows.

We need to confirm that
the code is working
after any changes.

Easy to write
Easy to read
Isolated
Composable

An example:
The bowling kata
(courtesy grabbed from Sebastian Bergmann)

10 frames

2 rolls to knock down the 10 pins

Score for a frame is the number of pins
knocked down

Bonus for a spare (all 10 pins knocked down in
two tries): next roll

Bonus for a strike (all 10 pins knocked down in
one try): next two rolls

Extra rolls for spare or strike in the 10th frame

<?php
require_once 'BowlingGame.php';

class BowlingGameTest extends PHPUnit_Framework_TestCase
{

}
?>

<?php

class BowlingGameTest extends
PHPUnit_Framework_TestCase
{
public function testScoreForGutterGameIs0()
{

}

}

<?php

class BowlingGameTest extends
PHPUnit_Framework_TestCase
{
public function testScoreForGutterGameIs0()
{
$game = new BowlingGame;
for ($i = 0; $i < 20; $i++) {
$game->roll(0);
}

$this->assertEquals(0, $game->score());
}

}

fullo@teletran ~ % phpunit --skeleton-class BowlingGameTest
PHPUnit 3.4.2 by Sebastian Bergmann.
Wrote skeleton for "BowlingGame" to "BowlingGame.php".

<?php
class BowlingGame
{

public function roll()
{
// Remove the following line when you
// implement this method.

throw new RuntimeException('Not yet implemented.');
}

public function score()
{
// Remove the following line when you
// implement this method.

throw new RuntimeException('Not yet implemented.');
}
}

fullo@teletran ~ % phpunit BowlingGameTest

E

Time: 0 seconds

There was 1 error:

1) BowlingGameTest::testScoreForGutterGameIs0
RuntimeException: Not yet implemented.
/home/fullo/BowlingGame.php:10
/home/fullo/BowlingGameTest.php:11

FAILURES!
Tests: 1, Assertions: 0, Errors: 1.

<?php
class BowlingGame
{

public function roll($pins)
{

}

{
return 0;
}
}
?>

fullo@teletran ~ % phpunit --colors BowlingGameTest

.

Time: 0 seconds

OK (1 test, 1 assertion)

We have to write the
tests when the code is
fresh.

<?php

{
// …

public function testScoreForAllOnesIs20()
{

for ($i = 0; $i < 20; $i++) {
$game->roll(1);
}

}
}

fullo@teletran ~ % phpunit –colors
BowlingGameTest

.F

Time: 0 seconds

There was 1 failure:

1) BowlingGameTest::testScoreForAllOnesIs20
Failed asserting that <integer:0> matches
expected value <integer:20>.

FAILURES!
Tests: 2, Assertions: 2, Failures: 1.

<?php
class BowlingGame
{

protected $rolls = array();

public function roll($pins)
{
$this->rolls[] = $pins;
}

{
return array_sum($this->rolls);
}
}

<?php

{
// …

public function testScoreForOneSpareAnd3Is16()
{

$game->roll(5);
$game->roll(5);
$game->roll(3);

// a function to to roll X times
$this->rollMany(17, 0);
}

}

fullo@teletran ~ % phpunit –colors
BowlingGameTest

..F

Time: 0 seconds

There was 1 failure:

1) BowlingGameTest::testScoreForOneSpareAnd3is16
Failed asserting that <integer:13> matches
expected value <integer:16>.

FAILURES!
Tests: 2, Assertions: 2, Failures: 1.

Tests can serve
as an executable
specification.

fullo@teletran ~ % phpunit --testdox BowlingGameTest

BowlingGame
[x] Score for gutter game is 0
[ ] Score for all ones is 20
[ ] Score for one spare and 3 is 16
[ ] Score for one strike and 3 and 4 is 24
[ ] Score for perfect game is 300

To write only clean
and useful code.

To easily iterate in
development design.

For more info see Sebastian
Bergmann's Bowling Kata
Workshop!

http://www.slideshare.net/sebastian
_bergmann/quality-assurance-in-
php-projects-2164371

Francesco Fullone
ff AT ideato.it
skype: ffullone

via Quinto Bucci 205
47023 Cesena (FC)
info AT ideato.it
www.ideato.it

TDD, a starting point...

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