public function testCustomAttribute()
{
$text = new Text('email');
$expected = '<input type="text" name="email" data-sample="test-value">';
$result = $text->attribute('data-sample', 'test-value')->render();
$this->assertEquals($expected, $result);
$expected = '<input type="text" name="email">';
$result = $text->clear('data-sample')->render();
$this->assertEquals($expected, $result);
}