class ProfileController extends Zend_Controller_Action {

private function getUploadAvatarForm()
{
    $form = new Zend_Form;
    $form->setAttrib('enctype', 'multipart/form-data');
    $form->setAction($this->view->baseUrl('/profile/upload-avatar'))
         ->setName('uploadAvatarForm')
         ->setMethod('POST');

    $element = new Zend_Form_Element_File('avatar');
    $element->setLabel('Upload an image:')
            ->addFilter('Rename',
                array('target' => '/path/toimages/directory/' . $this->userId . '.png',
                      'overwrite' => true)
            );

    $element->addValidator('Count', false, 1);
    $element->addValidator('Size', false, 102400);
    $element->addValidator('Extension', false, 'png');
    $form->addElement($element, 'avatar')
         ->addElement('submit', 'submit_upload', array('label' => 'upload'));
    return $form;
}

public function uploadAvatarAction()
{
    $form = $this->getUploadAvatarForm();
    $this->view->form = $form;
    if (!$this->getRequest()->isPost() || !$form->isValid($_POST)) {
        return;
    }
    if (!$form->avatar->receive()) {
        ... error...
    }
    ... ok ...
}

}

public function testUploadFile()
{
    $this->_doLogin('user', 'password');
    $this->getRequest()
         ->setMethod('POST'));
    $this->mockFileUpload();

    $this->dispatch('profile/upload-avatar');
    var_dump($this->getResponse()->getBody());
}

private function mockFileUpload()
{
    $_FILES = array(
        'avatar' => array(
            'name' => 'test.png',
            'type' => 'image/png',
            'tmp_name' => '/tmp/test.png',
            'error' => 0,
            'size' => 10127));
}

$class = new ProfileController();
$form = $class->getUploadAvatarForm();
$form->getElement('avatar')->setTransferAdapter(new MockAdapter());

class MockAdapter extends Zend_File_Transfer_Adapter_Http
{
    public function isValid($files = null)
    {
        return true;
    }
}