The document discusses efficient WordPress plugin development through software testing, emphasizing the importance of various testing methods including unit, integration, and behavior testing. It provides practical examples using the 'freifunkmeta' plugin and Vagrant for development environments, as well as automation tools like PHPUnit and Travis CI for continuous integration and deployment. The author advocates for a balance between testing and productivity, highlighting the need for tests to ensure software correctness without excessive overhead.

1. Effizientere
WordPress-Plugin-Entwicklung mit
Softwaretests
Martin Schütte

2. About DECK36
• Small team of 7 engineers
• Longstanding expertise in designing, implementing and operating
complex web systems
• Developing own data intelligence-focused tools and web services
• Offering our expert knowledge in Automation & Operation,
Architecture & Engineering, Analytics & Data Logistics

3. 1. Dev & Test Environments
2. Testing Variants
Static Code Analysis
Unit Testing
Integration Testing
Behaviour Testing
3. Integration & Automation

4. Main Questions
How can I know (my) software is correct?
How does my boss know software is correct?
How do I know software implements a given design?
How can we discuss what “correct” is, anyway?
We always need:
• implicit assumptions,
• explicit specifications.

5. Levels of Testing
..
abstract
.
specific
.
Unit Tests
.
Integration Tests
.
Acceptance
Tests

6. Example Plugin: Freifunkmeta

7. Use a Dev
Environment

8. Vagrant
Configuration tool for (VirtualBox) VM
setup and provisioning.
“Local cloud”
• Self service
• Instant provisioning
Useful for development
• reproducible environment
• independent PHP 5.x setups
• try things and not jeopardise
your dev environment

9. VagrantPress
$ git clone https://github.com/chad-thompson/vagrantpress.git
$ cd vagrantpress
$ vagrant up
will setup VM with:
• Ubuntu Precise (12.04), Apache 2.2, MySQL 5.5, PHP 5.3
• Wordpress 3.8
• phpMyAdmin
• PHPUnit
• phpcs, phploc, phpdepend, …

10. Testing Variants

11. Coding Style
$ phpcs --standard=WordPress freifunkmeta.php
FILE: [...]/plugins/freifunkmeta/freifunkmeta.php
---------------------------------------------------------------------
FOUND 360 ERROR(S) AND 406 WARNING(S) AFFECTING 338 LINE(S)
---------------------------------------------------------------------
21 | ERROR | Incorrect indentation; expected 1 space, found 4
22 | WARNING | Line is indented with space not tab
33 | ERROR | String "Unable to retrieve URL %s, error: %s" does
| | not require double quotes; use single quotes instead
322 | ERROR | Closing parenthesis of a multi-line function
| | definition must be on a line by itself
440 | ERROR | Expected next thing to be a escaping function,
| | not '"<option value='$city' $selected>$prettycity
| | </option>"'

12. Code Metrics
$ php pdepend_summary.php freifunkmeta.php
Package/Class Method LoC %Comment CCN NPath
------------- ------ --- -------- --- -----
FF_Meta output_ff_contact 49 6.1 10 384
FF_Meta shortcode_handler 41 2.4 9 48
FF_Community __construct 12 0.0 7 15625
FF_Meta register_stuff 18 0.0 5 16
FF_Meta aux_get_all_locations 23 8.7 5 6
FF_Community make_from_city 15 0.0 4 20
[...]

13. Example Plugin: Freifunkmeta
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

14. Unit Testing
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

15. Simple PHPUnit Test Case
class LowLevelTests extends PHPUnit_Framework_TestCase {
function setUp() {
$this->FFM = new FF_Meta();
}
function test_output_ff_state() {
$data = array("state" => array("nodes" => 429));
$ret = $this->FFM->output_ff_state($data);
$this->assertRegExp('/429/', $ret);
}
}

16. Unit Testing (contd.)
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

17. Integration Testing
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

18. Unit Testing with Mock Object
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

19. Example: Test with Dependency Injection
class MockDataService {
function get($url) {
return $some_fixed_data;
}
}
class WpIntegrationTests extends WP_UnitTestCase {
function setUp() {
parent::setUp();
// get plugin instance and replace ext. data service:
$this->plugin = $GLOBALS['wp-plugin-ffmeta'];
$this->plugin->reset_external_data_service(
new MockDataService() );
}
// ...

20. Example: Test with Dependency Injection
// ...
function test_post_ff_services() {
$post_attribs = array(
'post_title' => 'Test',
'post_content' => '[ff_services]' );
$post = $this->factory->post->create_and_get(
$post_attribs );
// w/o filter:
$this->assertEquals($post_content, $post->post_content);
// with filter:
$output = apply_filters( 'the_content',
$post->post_content );
$this->assertRegExp('/radio.ffhh/', $output);
}
}

21. PHPUnit Output

22. Behaviour Testing
..WP Blog.
FF_Meta
.
WP Core
.
Other Plugins
.
FF_Community
.
FF_Dir
.
Output
Formatter
.
HTTP Get
Service

23. WordPress Shortcode Plugin Test
..
Feature: Use Shortcodes
In order to use my Plugin
As a website author
I need to write posts with shortcodes
Background:
Given I am logged in as "admin" with "vagrant"
Scenario: Without the plugin
Given the plugin "freifunkmeta" is "inactive"
When I write a post with title "test" and content "[ff_contact]"
Then I should see "ff_contact"
Scenario: With the plugin
Given the plugin "freifunkmeta" is "active"
When I write a post with title "test" and content "[ff_contact]"
Then I should see "Twitter" in the ".ff_contact" element
And I should not see "ff_contact"

24. Behat Output

25. Implementation / Translation
A look behind the curtain:
• framework is clever but not magical
• some translation needed
• statements have to become executable code
Mechanism:
• plain sentence → method name
• quoted words → arguments
• matching with annotated regular expressions
• methods yield success, exception, or pending exception

26. Example: Behat Context (PHP)
/**
* from MinkContext
* Checks, that page contains specified text.
*
* @Then /^(?:|I )should see "(?P<text>(?:[^"]|")*)"$/
*/
public function assertPageContainsText($text)
{
$this->assertSession()->pageTextContains(
$this->fixStepArgument($text));
}

27. The Big Picture
..Features.
Step Definitions
.
WebDriver
.
Browser

28. The Big Picture
..Features.
Behat (PHP)
.
cucumber.js
.
Cucumber
(Ruby)
.
PhantomJS
.
Goutte
.
Selenium
.
Firefox
.
Chrome

29. Unit & Behaviour Testing
Unit Tests
• unit testing
• programmers
• programming language
• bottom-up
• assertXYZ
• tests derived from user stories
⇒ development tool
Behaviour Tests
• acceptance test scenarios
• non-developers
• language of business domain
• top-down / outside-in
• X should do Y
• execute user stories
⇒ design & communication tool

30. Automate!

31. Scripting
Basis for all automation.
Lots of useful builtins and packages:
• wp core download/install/config/…
• wp export/import
• wp plugin get/install/update/…
• wp scaffold _s/plugin/plugin-tests
• wp server

32. wp scaffold
Generate skeleton code for a new plugin & unit tests:
$ cd wordpress/wp-content/plugins
$ wp scaffold plugin-tests awesome
$ find awesome
awesome/
awesome/awesome.php
awesome/bin
awesome/bin/install-wp-tests.sh
awesome/tests
awesome/tests/bootstrap.php
awesome/tests/test-sample.php
awesome/.travis.yml
awesome/phpunit.xml

33. wp scaffold (contd.)
Create WP instance and run unit tests:
$ cd awesome
$ bash ./bin/install-wp-tests.sh wp_tests root vagrant latest
...
$ phpunit
PHPUnit 4.0.17 by Sebastian Bergmann.
[...]
Configuration read from [...]/plugins/awesome/phpunit.xml
.
Time: 5.52 seconds, Memory: 23.50Mb
OK (1 test, 1 assertion)

34. Version Control
• use version control!
• many possible workflows,
e. g. branches for dev and release
• use pre-commit hooks,
e. g. with php -l syntax check

35. Travis-CI
Continuous Integration service for GitHub
1. gets notified on push
2. builds project
3. runs phpunit
4. summarizes results,
alert on failure

36. Example .travis.yml
language: php
php:
- 5.4
- 5.5
- hhvm
env:
- WP_VERSION=3.8.3
- WP_VERSION=latest
before_script:
- bash bin/install-wp-tests.sh wordpress_test
root '' localhost $WP_VERSION
script: phpunit

37. Travis-CI Pass

38. Automated Testing
Target: no manual effort.
Continuous Integration:
• frequent code check-ins
• verified by automated
builds and tests
• quickly find bugs
and regressions
Continuous Deployment:
• (semi-)automated deployment
• plan for rollback

39. Costs and Benefits of Testing
• Testing (like Documentation) has a cost
• usually: productivity improvement > cost
• but find the right balance

40. Conclusion
I get paid for code that works, not for tests, so my philosophy is to test
as little as possible to reach a given level of confidence.
– Kent Beck
Links
• http://phpqatools.org/: PHP Quality Assurance Toolchain
• http://wpgear.org/: compendium of useful WP developer tools
• http://wptest.io/: test data for WP plugins and themes
• Ptah Dunbar: Automated Testing in WordPress, Really?!
• tuts+ articles by Tom McFarlin
• Conversation “Is TDD Dead?”

41. Thank You