public function testWalk()
{
$current = ['aBcDe', 'Jakub', 'ŽLUŤOUČKÝ kůň PĚL ďábelské ÓDY'];
$expected = ['abcde', 'jakub', 'žluťoučký kůň pěl ďábelské ódy'];
$input1 = new Fluent();
$input1->check($current, 'data')->filter('lowerCase')->validate('isArray');
$input2 = new Fluent();
$input2->check($current, 'data')->walk()->filter('lowercase')->validate('stringLengthGreaterThan', '', 4);
$this->assertTrue($input1->isValid());
$this->assertTrue($input2->isValid());
$this->assertEquals($expected, $input1->data);
$this->assertEquals($expected, $input2->data);
}