Testable Code ... In Joomla!?

TESTABLE CODE ..... IN JOOMLA!?
Old School Development Regenerated, or, Doin’ it like a Time Lord

Friday, March 15, 13

Who Is This?
Arlen Walker - (Paladin)
@arlen
Web Developer, PKWARE, Inc.


CURMUDGEON


ANNOYANCE


TROUBLEMAKER


ARROGANT


WASTE EVACUATION CHUTE


TEST NAZI


That’s Who, But Why?



40 years development experience




15 years on the web




15 years on the web

Wrote plugins when they were called Mambots




15 years on the web

Wrote plugins when they were called Mambots

Joomla Community Magazine Developer’s Workbench


What If You Had A Tool...


... that could look inside your application?



... that would help you write better code, faster?




... that encouraged good development practices?





... that conformed to the advice of major productivity gurus like
David Allen and Stephen Covey?





... that conformed to the advice of major productivity gurus like
David Allen and Stephen Covey?

...that pointed out what you’re doing now breaks what you did
last week?


Automated Testing

Kent Beck’s work on Smalltalk testing resulted in SUnit

From there, JUnit was born, and the xUnit series of testing
frameworks began

Joomla is written in PHP, so it uses ....


PHPUnit


Tests Before Code

Kent Beck remembered reading about the “tests first” approach
in an “ancient” computer programming manual.

This memory began what is known today as Test Driven
Development, an agile development practice that uses tests to
define the code that will be written.


Write Tests First?
Enforces "plan before code"

Focuses the coding on one task at a time

Documents progress

Avoids creating unnecessary code

Ensures resulting code is testable, therefore easily changeable.

Allows immediate refactoring of code, resulting in cleaner,
clearer, better code.


THE ONE CERTAINTY


YOUR CODE WILL CHANGE!


Testable Code is Easy to Change
Modifiable Code Testable Code
Small Units Small Units

Focused on Single Idea Focused on a Single Idea

Loosely Coupled Loosely Coupled

Clean and Clear Clean and Clear


DON'T JUST TAKE MY WORD
FOR IT


David Allen

Before you begin, answer one question:

“What does ‘done’ look like?”


Dr. Stephen Covey

Habit 2

Begin With The End In Mind


SO WHAT WOULD TESTABLE CODE
THAT WORKS IN JOOMLA! LOOK LIKE?


mod_random_image — Before
Requires presence of Joomla
code

Depends on specific classes

Must execute code outside of
unit to evaluate unit’s
performance

Harder to debug issues

Violates "Tell, Don't Ask"


Tell, Don't Ask

Procedural code asks for information, makes a decision, and then
acts

Object-Oriented code tells an object to act, and the object
decides what it can/should do


mod_random_image — After

Much simpler code

Easier to understand

All logic now inside object

Simply creates unit and
output

No real debugging necessary


Helper
Static functions
This means we can’t replace them
for testing purposes
Hard-coded to use Joomla
functions
Requires execution of external
code
Violates “Metz Prohibition”


“Never Mention a Class Name
Within Another Class”
From Sandi Metz

As with all rules of software development, it’s not inviolable.

The specific class is less important than its members

Liskov Substitution Principle

Reduces dependencies on outside code, makes doubling for
testing simple.


Helper
No static method calls
A completely different cms object
can be inserted for testing purposes.
Can be tested in isolation from all
Joomla code.
No violations of the Metz
Prohibition


Test Doubles

Special-purpose objects

Replace parts of a larger system

Receive messages from the code being tested

Report on their interactions with the code being tested

Supply test data


PHUnit Test Doubles
$this->mock_glue = $this->getMock('JoomlaGlue', array(
'getBaseUrl', 'strpos', 'getTranslatedText',
'getLayoutPath', 'sendHTML'));

$this->mock_glue->expects($this->once())-
>method('getBaseURL')->
will($this->returnValue('http://www.testingsite.com'));

Checks to be sure getBaseURL() gets called only once, and returns a specific value.

$this->mock_glue->expects($this->exactly(2))-
>method('strpos')
->will($this->returnValue($this->folder));

Checks to be sure strpos() gets called twice and each time returns a specific value.


What if it’s not a Module?

Plugins can be set up very similarly to Modules

An idea for Components is to use the Decorator pattern to wrap
your class around the Joomla class.


Decorator Pattern

Brings in the wrapped object in its constructor

Passes all calls it doesn’t handle itself on to the decorated class

"Prefer composition over inheritance"


Decorator

Include all decorated methods as pass-thru’s

... or use the “__call” magic method to pass method calls
public function __construct($client)

{
$this->decorated = $client;
}

... overridden and / or new methods here ...

// route all other method calls directly to the decorated object
public function __call($method, $args)
{
// you could also add method_exists check here
return call_user_func_array(array($this->decorated, $method), $args);
}


BUT I DO FRONT-END WORK!
I don’t have any way to test, right?


Yes, you can!

Template overrides can be tested like modules or plugins -- wrap
them with an object that provides links to the information they
need, replace them with test data for testing.

But PHPUnit can’t test javascript, can it?


Javascript

Selenium2 (WebDriver) works with PHPUnit, but:

Direct UI testing is Fragile

Direct UI testing doesn’t isolate the UI unit being tested

Direct UI testing takes longer than unit testing should take


Jasmine

In-Browser testing:

http://pivotal.github.com/jasmine/

Command line with phantom.js

https://github.com/jcarver989/phantom-jasmine

http://www.theodicius.net/archives/2012/09/25/what-i-
did-to-the-jasmine-phantom/


Jasmine
Uses a traditional behavior-focused english-like syntax:

describe - to set the description for a block of tests

it - to describe the specific test

expect - to match the actual output with the expected.

Jasmine-jQuery provides test fixtures and jQuery matchers

https://github.com/velesin/jasmine-jquery


A Block of Related Tests

describe( “Description of Test Block”, function () {

...test code goes here...

});


Test Setup And Teardown
beforeEach( function () {

.....set up for test to begin.....

});

afterEach( function () {

.....teardown from testing.....

});


Fixtures

Added by jasmine-jQuery

Allows you to create a special set of markup to test against.

setFixtures('<div class="event"><a class="showme"
style="display:none;">Show</a><a class="hideme"
style="display:none;">Hide</a><div
class="description">Description</div></div>');


Test

it( “What is test about”, function () {

.....actual test happens here.....

});


Match Results

expect(actualValue)[.not].toBe(otherValue);

other matchers include toEqual(y), toMatch(regex),
toBe[Un]Defined(), toBeNull(), toBeTruthy(), toBeFalsy(),
toContain(x), toBeLessThan(x), toBeGreaterThan(y)

jasmine-jQuery adds even more matchers


Jasmine Example


Originally
$('#webinar-click1').click(function() {
$('#webinar-desc1').show('fast', function() {
$('#webinar-click1').fadeOut('fast', function() {
$('#webinar-click-hide1').fadeIn('fast', function() {
});
});
});
});
$('#webinar-click-hide1').click(function() {
$('#webinar-click-hide1').fadeOut('fast', function() {
$('#webinar-desc1').hide('fast', function() {
$('#webinar-click1').fadeIn('fast', function() {
});
});
});
});


Tests
describe("Expanding Descriptions", function () {
! beforeEach(function () {
! ! setFixtures('<div class="event"><a class="showme" style="display:none;">' +
! ! ! 'Show</a><a class="hideme" style="display:none;">Hide</a>' +
! ! ! '<div class="description">Description</div></div>');
! });
! afterEach(function () {
! });
! it("should not have visible showme button", function () {
! ! expect($(".event .showme").first().css("display")).toBe("none");
! });
! it("should not have visible hideme button", function () {
! ! expect($(".event .showme").first().css("display")).toBe("none");
! });
! it("should display the description", function () {
! ! expect($(".event .description").first().css("display")).not.toBe("none");
! });
});


Initialization
describe("Initializing The Boxes", function () {
! beforeEach(function () {
! ! setFixtures('<div class="event"><a class="showme" style="display:none;">' +
! ! ! 'Show</a><a class="hideme" style="display:none;">Hide</a>' +
! ! ! '<div class="description">Description</div></div>');
! ! setExpandingBoxes();
! });
! it("should now have a visible showme button", function () {
! ! expect($(".event .showme").first().css("display")).not.toBe("none");
! });
! it("should not have a visible hideme button", function () {
! ! expect($(".event .hideme").first().css("display")).toBe("none");
! });
! it("should not display the description", function () {
! ! expect($(".event .description").first().css("display")).toBe("none");
! });
});


Credits
Jasmine S.O.L.I.D.
http://pivotal.github.com/jasmine/ http://butunclebob.com/
https://github.com/jcarver989/phantom- ArticleS.UncleBob.PrinciplesOfOod
jasmine PHPUnit
https://github.com/velesin/jasmine-jquery
https://github.com/sebastianbergmann?
http://www.theodicius.net/archives/ tab=repositories
2012/09/25/what-i-did-to-the-jasmine-
phantom/ Metz Prohibition
http://rubyrogues.com/087-rr-book-
Testable Modules clubpractical-object-oriented-design-in-
http://magazine.joomla.org/issues/issue- ruby-with-sandi-metz/
aug-2012/item/822-Towards-A-More-
Testable-Module Tell, Don’t Ask
http://www.ccs.neu.edu/research/demeter/
related-work/pragmatic-programmer/
jan_03_enbug.pdf


Arlen Walker

@arlen on Twitter

Paladin on Github

http://speakerrate.com/talks/20671-testable-code-in-joomla


Testable Code ... In Joomla!?

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