/**
  * @covers WPSEO_Meta::validate_meta_robots_adv
  */
 public function test_validate_meta_robots_adv()
 {
     // none should take precedence
     $this->assertEquals('none', WPSEO_Meta::validate_meta_robots_adv('none, something-invalid, noarchive'));
     $this->assertEquals('none', WPSEO_Meta::validate_meta_robots_adv(array('none', 'something-invalid', 'noarchive')));
     // - should take precedence
     $this->assertEquals('-', WPSEO_Meta::validate_meta_robots_adv('-, something-invalid, noarchive'));
     $this->assertEquals('-', WPSEO_Meta::validate_meta_robots_adv(array('-', 'something-invalid', 'noarchive')));
     // string should be cleaned
     $this->assertEquals('noarchive,nosnippet', WPSEO_Meta::validate_meta_robots_adv('noarchive, nosnippet'));
     $this->assertEquals('noarchive,nosnippet', WPSEO_Meta::validate_meta_robots_adv(array('noarchive', 'nosnippet')));
 }