$browser->
    get('/upload')->
    click('Upload', array('form' => array(
        'file1' => sfConfig::get('sf_test_dir').'/datas/test01.jpg',
    )))
;

<?php

include(dirname(__FILE__).'/../../bootstrap/functional.php');

$browser = new MyTestFunctional(new myBrowser());
$browser->loadData();

$browser->
    info('JPEGファイルをアップロードできる')->
    setUploadFile('file1', sfConfig::get('sf_test_dir').'/datas/test01.jpg')->
    post('/upload', array('title' => 'hoge'))->

    with('response')->begin()->
        isStatusCode(200)->
    end()->
;

<?php

class myBrowser extends sfBrowser
{

    public function setUploadFile($key, $filename)
    {
        if (is_readable($filename))
        {
          $fileError = UPLOAD_ERR_OK;
          $fileSize = filesize($filename);
        }
        else
        {
          $fileError = UPLOAD_ERR_NO_FILE;
          $fileSize = 0;
        }

        $this->parseArgumentAsArray($key, array(
            'name' => basename($filename),
            'type' => '',
            'tmp_name' => $filename,
            'error' => $fileError,
            'size' => $fileSize,
        ),
        $this->files);
    }

}

<?php

class MyTestFunctional extends sfTestFunctional
{
    public function loadData()
    {
        $doctrine = Doctrine_Manager::getInstance()->getCurrentConnection()->getDbh();
        $doctrine->query('SET FOREIGN_KEY_CHECKS = 0');
        $doctrine->query('TRUNCATE TABLE uploads');
        $doctrine->query('SET FOREIGN_KEY_CHECKS = 1');
        unset($doctrine);

        Doctrine::loadData(sfConfig::get('sf_test_dir').'/fixtures/');
        return $this;
    }

    public function setUploadFile($key, $filename)
    {
        $this->browser->setUploadFile($key, $filename);

        return $this;
    }
}