ExampleTaskTest.php

<?php
require_once(dirname(__FILE__) . '/../bootstrap/task.php');

# load fixtures of this plugin
$propelData->loadData(sfConfig::get('sf_plugins_dir') . '/yetAnotherPlugin/data/fixtures');

$limeTest = new lime_test(1, new lime_output_color());

$task = new ExampleTask($dispatcher, $formatter);
$task->run(array(), array());

$logs = $logger->getLogEntries();
$limeTest->like($logs[0], '/Task did log something/', 'Log entry found.');

task.php

<?php

// initialize configuration
$_test_dir = realpath(dirname(__FILE__) . '/..');
require_once(dirname(__FILE__) . '/../../config/ProjectConfiguration.class.php');
$configuration = new ProjectConfiguration(realpath($_test_dir . '/..'));

// initialize lime
require_once($configuration->getSymfonyLibDir() . '/vendor/lime/lime.php');

// add autoloader
require_once($configuration->getSymfonyLibDir() . '/autoload/sfCoreAutoload.class.php');
sfCoreAutoload::register();

// add propel database fixture loader
new sfDatabaseManager(ProjectConfiguration::getApplicationConfiguration('frontend', 'test', true));
$propelData = new sfPropelData();

class TaskLogger
{
  protected $logEntries = array();

  public function log(sfEvent $event) 
  {
    $params = $event->getParameters();
    $this->logEntries[] = $params[0];
  }
  
  public function getLogEntries()
  {
    return $this->logEntries;
  }
}

$logger = new TaskLogger();
$formatter = new sfFormatter(80);

$dispatcher = new sfEventDispatcher();
$dispatcher->connect('command.log', array($logger, "log"));