A very (very, very) simple unittest for WordPress

testplugin.php

<?php
/*
Plugin Name: WordPressTests
Plugin URI:
Description: Automated testing of WordPress
Version: 0.0.1-dev01
Author: Ralf Albert
Author URI: http://yoda.neun12.de
*/

if( ! class_exists( 'TestPlugin' ) ){

add_action( 'plugins_loaded', array( 'TestPlugin', 'plugin_start' ) );

class TestPlugin
{
	private static $plugin_self = null;
	
	private $errors = array();
	
	public $tests = array( 'TestScriptsEnqueued', 'StylesPrinted' );
	
	public function plugin_start(){
		if( null === self::$plugin_self )
			self::$plugin_self = new self;
		
		return self::$plugin_self;
	}
	
	public function __construct(){
		// allow to add&modify the list of tests to run
		$this->tests = apply_filters( 'tests_to_run', $this->tests );

		// Captain Hook
		add_action( 'shutdown', array( &$this, 'run_tests' ) );
		add_action( 'finish_tests', array( &$this, '_output' ) );
		
		self::$plugin_self = &$this;
	}
	
	public function run_tests(){
		if( empty( $this->tests ) )
			return false;
			
		foreach( $this->tests as $test ){
			if( class_exists( $test ) ){

				$errors = array();
				$e = new $test();
				$errors = $e->get_results();

				if( ! empty( $errors ) )
					$this->errors = array_merge( $this->errors, $errors );
			}
		}

		do_action( 'finish_tests' );
	}
	
	public function _output(){
		if( empty( $this->errors ) )
			return false;

		echo '<div class="testoutput">';
		echo '<h1>Errors from Tests</h1>';
		echo 'Beginn output<hr />';
		
		foreach( $this->errors as $error )
			printf( '%s<br />', $error );
			
		echo 'End output<hr />';
		echo '</div>';
		
		return true;
	}
	
} // end_class_TestPlugin

/* ---------------------------------------------------------------------- *
 * ----- test classes --------------------------------------------------- *
 * ---------------------------------------------------------------------- */
 
 class TestScriptsEnqueued
 {
	protected $errors = array();
	
	public function __construct(){
		$test_class = new MyClass_To_Test();
		$test_class->enqueue_scripts();
		$this->check_if_scripts_are_enqueued( array( 'myJavaScript' ) );
	}

	public function check_if_scripts_are_enqueued( array $scripts_to_test ){	
		$scripts_to_test = apply_filters( 'scripts_to_test', $scripts_to_test );

		global $wp_scripts;

		if( ! is_a( $wp_scripts, 'WP_Scripts' ) )
			$this->wp_scripts = new WP_Scripts();
		else
			$this->wp_scripts = $wp_scripts;

		$registered_scripts = $this->wp_scripts->registered;
		
		// check if script was registered (enqueued)
		foreach( $scripts_to_test as $test_script ){
			if( key_exists( $test_script, $registered_scripts ) ){
				$this->check_if_file_exists( $registered_scripts[$test_script] );
			}
			else{
				$this->errors[] = sprintf( '<strong>%s</strong> was not registered', $test_script );
			}
		}
	}

	public function get_results(){
		return $this->errors;
	}
	
	protected function check_if_file_exists( $script ){
		// check file exists
		$src = $script->src;

		$f = @fopen( $src, 'r' );
		if( ! $f )
			$this->errors[] = sprintf( 'Can not open <strong>%s</strong>', $src );
		else
			fclose( $f );
	}
 }

/* ---------------------------------------------------------------------- *
 * ----- class to test -------------------------------------------------- *
 * ---------------------------------------------------------------------- */
class MyClass_To_Test
{
	public function __construct(){
		// do some init
	}
	
	public function enqueue_scripts(){
		wp_enqueue_script( 'myJavaScript', plugins_url( 'js/myjs.js', __FILE__ ), false, false, true );
	}
} 

} // end_if_class_exists