FileExtension validor error in Form context

$form = new \Zend\Form\Form();
  $form->add(array(
	'name' => 'test_file_input',
	'type'  => 'Zend\Form\Element\File'
));

$inputFilter = new \Zend\InputFilter\InputFilter();
$inputFilter->add(array(
'name' => 'test_file_input',
'required' => true,
'validators' => array(
	array(
      'name' => 'File\Extension',
      'options' => array('extension' => 'mo')
  )
)
));
$form->setInputFilter($inputFilter);

//Fake datas for test
$_FILES = array(
	'test_file_input' => array(
		'name'  => 'testsize.mo',
        'type'   => 'text',
        'size'   => 200,
        'tmp_name' => __DIR__ . '/_files/testsize.mo',
        'error' => 0
	)
);

$form->setData($validDatas)
$form->isValid(); // Error : stream_resolve_include_path() expects parameter 1 to be string, array given