/**
* test attribute disabled
*/
public function testInputDisabled()
{
$input = new TextInput('test');
$this->assertNull($input->renderDisabled(), 'Initially disabled is null');
$input->setDisabled('invalid');
$this->assertNull($input->renderDisabled(), 'Giving an invalid option should not change disabled');
$input->setDisabled('disabled');
$this->assertEquals(' disabled="disabled"', $input->renderDisabled());
$input->setDisabled('readonly');
$this->assertEquals(' readonly="readonly"', $input->renderDisabled());
$input->removeDisabled();
$this->assertNull($input->renderDisabled(), 'removeDisabled should remove the attribute value');
}