public function testFrozenOutputIsMasked()
 {
     $input = new HTML_QuickForm2_Element_InputPassword('foo');
     $input->setValue('bar');
     $input->toggleFrozen(true);
     // wow, never used lookbehind assertions before
     $this->assertNotRegExp('/(?<!value=")bar/', $input->__toString());
     $input->persistentFreeze(false);
     $this->assertNotRegexp('/bar/', $input->__toString());
 }