/**
  * @dataProvider dataProviderIsInvalid
  */
 public function testIsInvalid($data, $messages)
 {
     $filter = new ContentNegotiationInputFilter;
     $filter->setData($data);
     $input = $filter->get('selectors');
     $this->assertFalse($filter->isValid());
     $this->assertEquals($messages, $filter->getMessages());
 }