testable code ... in joomla!?
DESCRIPTION
Writing testable code is also writing better code. Here's how to do it in the context of Joomla CMSTRANSCRIPT
TESTABLE CODE ..... IN JOOMLA!?Old School Development Regenerated, or, Doin’ it like a Time Lord
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Who Is This?Arlen Walker - (Paladin)
@arlenWeb Developer, PKWARE, Inc.
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CURMUDGEON
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ANNOYANCE
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TROUBLEMAKER
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ARROGANT
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WASTE EVACUATION CHUTE
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TEST NAZI
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That’s Who, But Why?
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That’s Who, But Why?
40 years development experience
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That’s Who, But Why?
40 years development experience
15 years on the web
Friday, March 15, 13
That’s Who, But Why?
40 years development experience
15 years on the web
Wrote plugins when they were called Mambots
Friday, March 15, 13
That’s Who, But Why?
40 years development experience
15 years on the web
Wrote plugins when they were called Mambots
Joomla Community Magazine Developer’s Workbench
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What If You Had A Tool...
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What If You Had A Tool...
... that could look inside your application?
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What If You Had A Tool...
... that could look inside your application?
... that would help you write better code, faster?
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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?
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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?
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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 pointed out what you’re doing now breaks what you did last week?
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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 ....
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PHPUnit
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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.
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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.
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THE ONE CERTAINTY
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YOUR CODE WILL CHANGE!
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Testable Code is Easy to Change
Small Units
Focused on Single Idea
Loosely Coupled
Clean and Clear
Small Units
Focused on a Single Idea
Loosely Coupled
Clean and Clear
Testable CodeModifiable Code
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DON'T JUST TAKE MY WORD FOR IT
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David Allen
Before you begin, answer one question:
“What does ‘done’ look like?”
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Dr. Stephen Covey
Habit 2
Begin With The End In Mind
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SO WHAT WOULD TESTABLE CODE THAT WORKS IN JOOMLA! LOOK LIKE?
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mod_random_image — BeforeRequires 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"
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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
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mod_random_image — After
Much simpler code
Easier to understand
All logic now inside object
Simply creates unit and output
No real debugging necessary
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Helper
Static functionsThis means we can’t replace them
for testing purposesHard-coded to use Joomla
functionsRequires execution of external
codeViolates “Metz Prohibition”
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“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.
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HelperNo static method callsA 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
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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
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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.
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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.
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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"
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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); }
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BUT I DO FRONT-END WORK!I don’t have any way to test, right?
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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?
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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
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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/
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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
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A Block of Related Tests
describe( “Description of Test Block”, function () {
...test code goes here...
});
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Test Setup And Teardown
beforeEach( function () {
.....set up for test to begin.....
});
afterEach( function () {
.....teardown from testing.....
});
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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>');
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Test
it( “What is test about”, function () {
.....actual test happens here.....
});
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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
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Jasmine Example
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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() {
$('#webinar-click1').fadeIn('fast', function() {
});
});
});
});
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Testsdescribe("Expanding Descriptions", function () {! beforeEach(function () {! ! setFixtures('<div class="event"><a class="showme" style="display:none;">' +! ! ! 'Show</a><a class="hideme" style="display:none;">Hide</a>' +! ! ! '<div class="description">Description</div></div>');! });! afterEach(function () {! });! it("should not have visible showme button", function () {! ! expect($(".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");! });});
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Initializationdescribe("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");! });});
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CreditsJasmine
http://pivotal.github.com/jasmine/https://github.com/jcarver989/phantom-jasminehttps://github.com/velesin/jasmine-jqueryhttp://www.theodicius.net/archives/2012/09/25/what-i-did-to-the-jasmine-phantom/
Testable Moduleshttp://magazine.joomla.org/issues/issue-aug-2012/item/822-Towards-A-More-Testable-Module
S.O.L.I.D.http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod
PHPUnithttps://github.com/sebastianbergmann?tab=repositories
Metz Prohibitionhttp://rubyrogues.com/087-rr-book-clubpractical-object-oriented-design-in-ruby-with-sandi-metz/
Tell, Don’t Askhttp://www.ccs.neu.edu/research/demeter/related-work/pragmatic-programmer/jan_03_enbug.pdf
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Arlen Walker
@arlen on Twitter
Paladin on Github
http://speakerrate.com/talks/20671-testable-code-in-joomla
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