public function testClearCaptchaSession()
 {
     $ses = $this->getMock('HTML_QuickForm2_Element_Captcha_Session_Mock', array('clear'));
     $ses->expects($this->once('clear'))->method('clear');
     $tc = new HTML_QuickForm2_Element_Captcha_Numeral();
     $tc->setSession($ses);
     $tc->clearCaptchaSession();
 }